The value of a specialty cert is exaggerated. I got a stack in the first few months after my OW and no one has ever asked for them. (It would take awhile to find them in my dive junk they are so deeply buried by now.) I bring only my AOW and nitrox (although it’s very unlikely I’ll get to use nitrox for various reasons) cards now because I know they won’t ask for the others. No one will stop you from diving if you DON’T have those certs. If they did hardly any boat dives would occur since so few people go to the trouble to obtain them. The industry has a hard enough time getting people in the door and do their OW without making anymore barriers for them. The issue with certs is some boats won’t take you to some sites (particularly deep ones) without AOW or experience with diving deep (100ft or more). And even if you have a cert they may want to restrict you to a less advanced site until they have a chance to observe you themselves and see that you can handle yourself well. (Just because you have a cert doesn’t mean you know what you’re doing!) Some shore accessible sites (caves usually) will also restrict you. You have your OW and AOW so you’re pretty much good to go for most non-technical dive sites in the Americas. I’ve been lots of places and done diverse types of dives and if I had stopped at OW I could have still done all of those dives safely. I learned by taking courses but I learned more by getting out and diving. But those courses can still be fun and instructional if you have a GOOD instructor, time, and money to do them. Take the courses that you think will be fun.