For the BMW yeah. It has been useful for some BMW-specific things for sure. I don't like that it's a $60-70 annual subscription on top of the cost of the data link dongle.

For other cars I either use my $20 basic wired reader for fast code-getting, or if I want live data I use one of the cheap wireless dongles (this one) and the Torque app (free). No issues so far with it though I don't use it often.