I think this has been answered pretty well. I would just add/emphasize that the only way to really know what is going on will be to, at minimum, sand down to whatever is beneath the paint. And, very likely, beyond that. Even if this turns out to be superficial cracking, its repair is not trivial. I see some things that suggest this is fairing over the underlying structure. But, also some things that suggest that the underlying structure was compromised.
Again, just speculation until you sand down to bare material and have a proper look. Ultimately, you will need to grind down to remove all compromised material, at minimum, but you might be able to see what's going on by just removing the paint.
A good surveyor will be able to tell you what is "probably" going on. But, I would not run the engine without doing a proper fix. I would be surprised if this did not involve underlying structural compromise.
One thing that makes me go "Hmm..." is that little wet patch in the upper end of the crack. Very hard to say because I don't have any other context for the photos, but unless we had a good explanation for why there is moisture there, I would be inclined to think that crack runs deep. At worst, that is water making its way from the bilge. More likely, it is water retained in the crack from being sprayed - but even then, it suggests this is more than just a shallow surface crack.
I would be very cautious about this. I don't know what the asking price is, but the repair cost could potentially approach the purchase price. If you purchase, you might get a great deal. Just get a reliable estimate for the repair and factor that into the price. If the repair is done properly, you will be better off than if nothing had been overtly wrong in the first place.
Don't have the current owner do the repair as a condition to the sale. If you do, they will not be incentivized to do the repair properly - just cheaply.