Though no one on ScubaBoard suggested it when I was looking into my first trip 10 years ago, and I don’t recall anyone having suggested it until this thread, the thought of using a marker did occur to me. However, there are several reasons I have never tried it. The first is what I mentioned: if everyone did that, there could be as many as half a dozen buoys all roughly in the same area, possibly leading to confusion. Another reason is that I am concerned someone might take my buoy, and I’ll waste a lot of time looking for it, and then after not finding it I’ll never be sure whether I missed it or someone took it. Also, it occurs to me that despite being pretty good at judging where my exit should be, if I somehow can’t find my buoy then I’m guilty of leaving junk on the reef. That’s the last thing the relative pristine/protected reefs of Bonaire need. And at night, others might find a flashing strobe obnoxious. You have obviously made your decision, but those are some things others might wish to consider before they decide to use a buoy.
The reef features don’t “all look the same” if you take the time to cement some reasonably distinctive feature in your mind.