Will I be missing anything important by skipping these? I'm most concerned with getting the best Cat Armor upgrades and I think those are all found in maps sold by blacksmiths and armorers. Is that correct?

All smuggler caches are just low level random loot. There are *no* Witcher diagrams or any other quest items within caches. You will not miss anything important.

for the most part they contain swords, armours, stones, horse gear and sometimes food and other sundries. they dont contain anything vital to the game, but are a great way to build up your money

Are good only for money, take me 10 hours to loot all of them, with boat...

Thanks for the help, everyone! I'm going to skip them for now unless they aren't too far out of my way. I have almost $30,000 gold with nothing to really spend it on.

If you have the Blood & Wine expansion and are going for the Grand Master armor, you might want to hit a few of these as you're going to need quite a bit of dimeritium ore, which is rare and expensive. You'll find it more commonly at the points of interest, including the smuggler's caches in Skellige.