The last place I put things is the seat. It makes it hard to swing your leg over when getting on or off. Except when riding to work that spot is reserved for my wife and she gets on after I do. After I put side bags on my Vulcan 15 years ago I don't think I will have a bike without them. Not a problem in 49 states so until that changes (hope- hope) they are my go to.The logical tight convenient solid spot for an every-ride kit is the pillion spot,
not the tank (hinderance and scratches, too small anyway),
not the top case (too far behind and can't take the 20+lbs of usual kits counting tools, water, etc...),
not side cases (some would say dangerous, I say nightmare in traffic).
Process of elimination says: tail bag.
Honda says: doh!
With my gen 2 650 I still have to remove the seat to access the helmet holders and I do that much more often than I fill up with gas, except when on a long ride.
The Honda was on my short list of bikes when I got a deal on the Versys.