Seattle's raising of the minimum wage was arguably symbolic.

Seattle--a world-class tech nexus point--raising its minimum wage affected a relatively small percent of businesses compared to a "normal" city, as businesses in Seattle would have long since needed to offer higher wages in order to keep employees.

I'd be much more interested in seeing the effects of a $15 wage in Nowheresville, USA than in Seattle.

Symbolic for maybe people that are making above minimum wage but an increase in minimum wage to $15 made so many people lives easier.

Well, that's both the point and missing the point. Seattle's higher minimum wage represented an already-existing reality in Seattle: their top-heavy economy.

"Normal" towns' leaders would recognize it as virtue-signaling rather than transformative change, because it would've affected proportionally few people.

The Seattle study was done during a time period when the economy of the city was going up significantly. The authors write in the paper that it's possible that if the minimum wage was not raised, it could have resulted in even more people employed.

Can you point me to a study other than the one in Seattle? I have only read about Seattle but have not really researched it thoroughly.