With the traffic -- those big electric bikes especially -- Chinese cities are no place for youngsters to peddle around sightseeing. Just walking is dangerous enough these days. Seriously.
I was thinking of bikes mainly as a means to move around low traffic hutongs and the like, not major roads.
Switching subtopics back to Didi/taxi, I prefer taxis from airports, train stations, and anywhere else where linking up with a driver could be difficult. But, if my pickup location is easy to spot, then Didi wins.