My ex is doing this in order to make the car payments on his car. Lyft has a lot of control over you, if you have phone problems you are screwed (his data has cut out in the middle of rides and such). Plus, as others have said, you have to have a nicer, newer car in order to even drive, which is not very frugal in and of itself.
I think it is something you should look into only if you really love to drive. A lot.