I would also support tipping via Venmo, Cash App, or Zelle for those who aren't willing to keep cash on hand. The goal is to tip out of band to prevent the usual gig app shenanigans, further harming gig workers beyond the usual gig work transactional arrangement.
If you don't want to support the "gig economy" then it is better not to use the apps. Cash payments will never lead to improvements in working conditions, pensions or health insurance.
