Cape Dory is famous for this problem, and it's the result of overly thick gelcoat, which is not that flexible. Temperature swings with the seasons expand and contract
the gelcoat and eventually it cracks. Happens faster in colder climes with decks that are not protected from ice.
It is cosmetic, but gelcoat does provide something of a protective layer for the underlying glass laminate. If you don't care how it looks, buff it and wax it and keep it waxed as best you can to keep water
Fixing it is a LOT of work, and I know from first hand experience redoing the deck on my Valiant. It was the third boat built in Texas
and in a conversation with Valiant they did admit that they may have laid it on a bit too thick on the first few boats.
The issue is that 90% of the cracks, even if they look like simple crazing, go down into the first schedule of laminate. While this is not a structural issue, any attempt to repair without also repairing the laminate will almost always result in the cracks coming back...either through a gelcoat repair or paint. If you grind off the gelcoat it may look fine until you wipe the bare fiberglass
down with acetone. You'll see a fine hairline crack in the glass if you look closely before the acetone flashes completely off.
I had extensive crazing around my cock pit and the deck hatches. I had to grind it all down and repair the laminate with a fresh layer, then fair, in preparation for paint. It was a long hard job.
As for whether you should walk away...if you don't care how it looks, and would be content to clean and wax it on a regular basis...it'll be fine probably for as long as you own the boat. At some point the gelcoat is going to start chipping up but that could be a long way off in the future.
EDIT: I just actually looked at the photos. That's pretty extensive and all over. I don't know that I'd be comfortable with that unless I just wanted a boat to sail and not worry about the future.
In particular, in the second to last photo
, under the block that looks like a stress crack and what is concerning is it's not just a fracture, it's actually pushing up, which is from water
getting in and freezing. While it may only be under the gelcoat, it's more severe than your general "crazing".