Your use case is in no shape or form spam or bloat, it's the most simple transaction possible, it doesn't matter if it's a self transfer, that happens all the time when people consolidate transactions. I can even decide to just send to a different wallet that it's also mine. People won't also be creating dns entries in your system all the time. My only question is if to your system if I can afterwards consolidate the transaction or do I need to keep it untouched, otherwise I would say don't worry.