I have an SMB with me, but I've never needed it on Bonaire. Car and house keys go into one of those waterproof 'diver egg' dry boxes, as does some money, my fill card* and my nature tag receipts**. Drivers license** goes in a wet pocket. If you really want to be sure, there's these cheap and ultra small Chinese dumb phones which would fit inside such a dry container.
* I have my own tanks here, you don't need this if you have a diving package
** the Nature tag gives you free access to the park, but you need the receipt (which has your name on it) as welll as a form of ID. If not, you pay the regular entry fee. Only take these when planning to go to the park.