It looks to me from the video that the stock attachment points for the main sheet are about 2/3rds of the way forward on the open hatch. You
could make a raised traveler bridge over the hatch, but it's true that would make it much more difficult going in and out of the cabin. Most boats with mid-boom sheeting and a cabin top mounted traveler have it just at the aft end of the hatch when slid open.
There are many good reasons to have a traveler, because it really improves sail control. For a fractional rig, the main sail sails in a relative header compared to the jib, due to upwash off the jib, and circulation around both sails. Therefore, for optimum speed while pointing, and max pointing angle, bringing the traveler up to windward so the boom is on centerline will allow the main to draw better, particularly in lighter winds. The other main reason to have a traveler for sailing close hauled is that the mainsheet then becomes your control for leech tension, and thus twist, and no longer handles angle of attack. The traveler is used to adjust angle of attack. The top of the sail is designed to fall off to leeward (twist.) This is because the wind up at the top of the mast is moving faster than the wind at water's surface due to friction. Faster wind also moves a bit aft, so if the main were a plywood board, you'd have the bottom sheeted and trimmed, but the top would be over-trimmed, not twisted off, causing stalling, drag, and more heeling. By using the mainsheet as leech tension, you can allow the top to twist off and be trimmed to the faster wind up high. As the wind gets faster, the speed differential isn't as much, and you trim for less twist, so more mainsheet tension. And as puffs hit, you can drop the traveler down for less power, or to accommodate shifts. This is really much more of concern to racers, who would play sail trim constantly to the wind for maximum speed and pointing, though of course proper sail trim is proper no matter if you are racing or not. Also, you can't see any of this without a good set of leech telltales at the end of each batten pocket.
Should you do this mod to your boat? That depends on why you are doing it. From your question, I assume that you are not an experienced sailor, or very knowledgable about sail trim. Which is perfectly fine; we all can always learn more about sail trim... but you have much to learn about trim on the boat you have and its rigging as set up by the designer. This is a very good book on learning the basics of sail trim:
https://shop.sailboatowners.com/prod.php?51998/Sail+Trim+Users+Guide
Case in point, I want a traveler on my boat, but I have decided that for the cost and the tradeoffs in convenience or liveability of the boat, I won't try to rig a traveler. Also, my boat isn't raced extensively, nor would it be a good racer if I tried to race a lot. So I have learned to do the next best thing to a traveler: vang-sheeting. Essentially, I overcome the weight of the boom and the effects of over-sheeting the mainsheet, by using my adjustable topping lift and vang to set the boom height and thus the amount of twist that I want, and then the mainsheet just does as good a job as it can dealing with angle of attack. Since I have no traveler, I'm never able to sheet the boom to the centerline for tightest pointing. Sometimes in light wind I will reach up and pull the boom to the centerline, which has allowed me to point a degree or two higher to avoid obstacles, but is probably not any faster. For my boat, cracking off a degree or two from pinching to gain boat speed is probably the fastest way to windward anyway.
If you get Don Guillette's book (which you should, from my link above which supports this forum) keep in mind when he's talking about the traveler, since you don't have one, you'll need to translate that advice on leech tension to vang sheeting techniques. Since I haven't expressly said it yet, for boats without a traveler, trying to sheet the main very hard in an attempt to get as close an angle of attack over tensions the leech, removing twist, and over trims the top of the sail, which is draggy and slow.
While I love making mods to boats, and tweaking them to suit my needs, when it comes to major changes like sail plan, or adding a traveler, etc. my advice is to NOT to do it. Sail the boat as it is, and get the most out of it that you can. If you determine you can't, then look for a different boat. There are so many used fiberglass boats available anymore, you should be able to find one that meets more of your needs. My advice on taking a boat with an existing traveler, like say, a pin-stop track, and upgrading it to a ball bearing car with easy to control remote purchase lines, is to absolutely do that upgrade. It will allow you to trim so much more easily than pin track. Of course, if you upgraded a traveler equipped boat like this, you would also want to install remotely adjustable jib leads. Because now you'll have easily adjustable controls to get the max out of the boat.
Also, all that control advice applies to new or new-er (less than 5 year old?) sails. If the sails are soft, blown out bedsheets, there's no way your sail controls will be able to affect the shape anyway.