Nothing wrong with self promotion. When you're starting out with anything in general, a lot of it will be you putting yourself (or by extension your bank) out there. I would say that if the bank is of a lower quality than your audience is accustomed to using, then that may turn people off from wanting to use it, but then... some people don't mind a fixer-upper or a bank that's not HQ. Just be mindful and don't shove your bank down everyone's throat to the point where it's spamming. If possible, find UTAU choruses to sign up for (My Favorite Vocaloid Songs Medley 1, 2, and 2015 are popular. Nico Wonderland as well) and sign up for an empty slot. UTAU users on Deviantart tend to do these quite a bit. They're an easy way to get free promotion and since people will be looking for banks to fill each ust, you don't have to feel bad or feel like you're annoying anyone.