If you're going to Bonaire and are only going to dive from the dock at one of the resorts your slip on fins will be fine.
That's true, but I'd add some caveats:
1.) On a Bonaire trip, you'll likely do 10 dives at a minimum (if you're also doing other things & aren't that big into diving, or get sea sick easily & blow a couple of days), more likely around 15+, and 20+ is quite possible.
2.) Not all resorts are ocean front, or have good dive sites right off their shores. I've stayed at Eden Beach Resort 4 times; they've got a wooden pier. But, they don't have much 'reef' - more a rubble site, with the wreck of the
Bakanal to swim out to. I like it, but no way would I only dive that site, all week. Buddy Dive (and maybe Captain Don's, if I remember right?) is said to have a really nice reef site (as resort dive sites go).
3.) To sum it up, you'll spend the week listening to others talk about hitting sites up & down the west coast such as Karpata, Tolo/Ol'Blue, Oil Slick Leap, Windsock, Invisibles, Hilma Hooker, Angel City & so on, and you'll be...diving off the resort pier over & over. It just won't happen. You'll at least turn to boat dives.
4.) Be mindful that part of the Bonaire trip is doing the first dive under supervision to establish you can control your buoyancy before they give you your marine park tag. Our group usually heads out to the Invisibles for that, since there's a big stretch of sandy bottom between the shore & reef. So whoever your group leader is, or whichever dive shop will be providing the service, you'll want to find out what they're got in mind if you plan to go 'bootless.'
Richard.