Future fins have no gap between the fin and the board, just like glassed on fins, but you can change fins for different conditions. They wont pop out of your board like a FCS set up can do in heavy situations. Glassed on fins are really cool, but if you ding one its a problem fixing it, where a fin system you can replace it. One time I remember having these hi tech carbon future fins in my backpack, and I was too lazy to change them out with the plastic ones the board came with. One session it was firing, and my board wasn't making sections, and the fins were humming, so I finally changed fins. Lo and behold, I was flying around sections, getting into pockets and shredding and going really fast, and I laughed my ass off at my own ignorance. Do not be tricked into thinking you have the right fins for your board until you try a few combos. On big days, I have a 6'6" Orion swallowtail that is too loose for a big drop when I use the G 3s or even G 5s. So I plug in my old Sunny Garcias and it holds big bottom turns. When it gets smaller, like waist to chest, I can put a small trailer fin in the back and throw tail. so keep you options open and get a removable fin system. I recommend Future shapes cause they are almost like glass ons, but more fun.
Thinking about a bonzer with a box in the middle and glass on on the sides.
as LBCrew stated, that's the norm for bonzers. i've never had any issues traveling w/ them, & i've trucked my bonzers all over the place, costa, panama, maldives...never a problem whatsoever. those little side fins are so low profile that it's really hard for even the most determined of baggage handlers to apply the requisite force necessary to damage them through a well-packed boardbag.
what kind of bonzer are you thinking about getting? pm me if you don't want to go off-topic; i'm kind of a bonzer nerd.
Replacing a fin is pretty much the same as replacing a fin box... shops might tell you otherwise, but in my own experience not much of a difference. If I hit a rock the whole box goes... not just the fin. Just my two pennies.
I don't think it's worth it. You might feel a little difference, but the convenience of switching fins and removing for travel outweighs the performance... If that becomes your "go to" board it will be a pain in the ass when you want to travel with it.
I had a board made with glass ons of the fins I prefer and I feel no difference between that board and the one I have with FCS.
Glass-on fins have the stiffest base possible (they're part of the board) and transfer force most efficiently. Some finbox systems have stiffer bases than others but chances are you wouldn't feel the difference between any fin system vs. glass-ons