Yeah. It uses google ad-mob, or if you purchase it needs the google play store app to verify that and deactivate ad-mob.
A way to purchase it without going through gplay would fix this, and probably means it could be published on fdroid in a premium-only version at least. I’ve been meaning to ask @[email protected] about the feasibility of that for a while now. It’s bothered me for years now, but I simply couldn’t find an alternative so far (neither back on reddit in the days).