I think the way to have this cake and eat it too is to personally be an extraordinarily good cash tipper. You'll still be supporting the system, but you'll ameliorate your personal use of it.
Adding tips will probably just cause the business to lower the wages, making the workers more dependent on a semi-random stream of tips instead of a fixed income, making life worse for them. Restaurants now work like that, and workers are voting with their feet. No need to extend this to other industries.
If it's a cash tip the app doesn't know it happened. It's not like restaurants. No manager is there to make everyone count up their tips at the end of the shift.