I use a utility knife everyday dozens of times. Open boxes but mostly to cut nylon fabric (Cordura and lighter). I sharpen my replaceable blades and get months/years out of each blade. Not because I am cheap, but because I need a sharper edge than the utility blades come with. I have yet to see one that comes from the factory truly "razor sharp" (and trying to strop one would likely be heck on your strop).

It is very simple to sharpen a straight edge like this. Just pick a shallow angle and rub the blade back and forth on the stone several times with the edge of the blade holder parallel to the stoneas a guide. Then flip it over and do the same on the other side. I just use a simple fine grained pocket stone with no oil or water.

I see where glue etc. would make a mess of things, but I would just keep a second knife for those purposes.

You can get tiny utility knives that fit on a key chain if box opening is the only use.