I also dislike scrawled low-effort tags. They’re an act of selfishness, making work for others to clean up. They don’t show any skill other than sneakiness of getting it done. No one wants to see that junk. They are not good.
That said, I’d still prefer crappy tags rather than ads. I hate the ads and the manipulative power of advertising. So if there was somehow a choice between crappy tags vs high-quality ads, I’d choose the tags. (But obviously, that’s all a moot point. Higher quality art / graffiti would be better than both other options. Obviously.)