I mean, yeah. You give up one thing and gain another. For instance, it would be much easier for people speaking those other "dialects" to learn to speak and u

I mean, yeah. You give up one thing and gain another. For instance, it would be much easier for people speaking those other "dialects" to learn to speak and understand putonghua, if they were seeing a phoenetic form of putonghua all around, rather than seeing characters which they read in their own words. Alternately, we could all replace our spoken languages with Chinese characters. Then we could all read Chinese subtitles, and reach each others' languages to some extent. But I think you'd be hard pressed to find anyone not already using Chinese characters for their own language who would consider the benefits worth the cost. It seems to me (as an outsider who's been studying the language for a few years) a sort of linguistic "Stockholm syndrome".