Yeah, I don't get it. I'm not Jaco, and wouldn't rate myself higher than intermediate/advanced, but I have no problem playing the unlined board, with only side dots in the correct places at 1, 3, 5, 7, etc. Plus my dots on the side of unlined board are small and barely visible in a dimly lit room. I think by the six month point concentrating on fretless I was pretty locked in on the lined board, which has dots in the wrong positions, and now a few months later don't even have to look at it. Only been playing the unlined fretless for a week, no problem.
I'm not bragging, just saying it's not that hard. Can't be, if I can do it.
IMO, I don't think the center dots are at all important on either fretted or fretless. That said, It is nice to have some decoration at the 12 fret position. Looks good, breaks up the board visually. I forget which brand puts a Dolphin there, Jackson? That's nice!