I would have thought overkill. A bandsaw can be set up very well but I wouldn't expect it to be able to produce glue ready mitres.
I bought a 2nd bandsaw once without a mitre gauge. I wasn't actually tempted to get one for it. I can see how they can be useful to help with cross cutting and flag stops could be handy but incra accuracy is a waste.
You might want to check the slots on your bandsaw first. Slots on my RP350S ae much too small for the Incra mitre bar. More disappointingly, when I upgraded my tablesaw recently that too had smaller mitre slots so I was gutted my lovely Incra was now redundant.
I do agree that the HD is probably overkill, I have seen glue ready cuts from a bandsaw so if nothing else im chasing the dream and seeing what other uses I can find for it, I could also use it on the router table.....and im not discounting a new table saw in the future
the mitre slot is 19mm so im pretty sure thats fine.