Blisters are the most over-worried-about issue with fiberglass. Mostly, people just don't like the idea of them, but they are typically only cosmetic. Depth matters. In the case of dime-sized blisters, these are not deep enough to matter, structurally. They are very unlikely to develop into something that is ever more than a cosmetic issue.
It is true that a complete and permanent repair is either expensive or time-consuming. But, it also doesn't need repair. It is relatively rare for a blister to extend into the laminate layers and, even then, is rarely a safety issue.
Does it affect resale value?
Well, it might if the blisters are not factored into the price you pay. That is, if the seller prices accordingly, then you should be able to sell accordingly. But honestly, if you buy a 1988 Catalina with the expectation that there will be no blistering, you narrow your search by quite a bit. They are a pretty normal thing - most boats of that age have some. However, Catalina 30s are increasingly being consider entry-level boats - meaning first-time buyers. First-time buyers will, in general, worry more about blisters than a more seasoned boat owner.
So, there's that. You didn't say, but I am inferring that this is your first boat. And, the blisters are giving you pause. So, they are likely to give the next buyer pause too.
A surveyor will look at the blisters and tell you that they are not a structural concern and not something that even needs repair - possibly ever. But, first-time buyers are often more influenced by gut-feelings and emotions.
When I bought my current boat (a 1975) we hauled her out for inspection. I assumed there would be some blistering, and that it might be fairly extensive. As long as there were none that appeared to run deep (which would be unusual), the blistering that you described would not have affected my purchase decision one bit. I had already assumed it was there, just due to the age of the boat. As it happens, there was none at all. I mention this only because everyone (me, the surveyors, and the previous owner) was surprised by the absence of blistering - which says something about how common blisters are.