Ethical Considerations of Using Cash Apps

“Can I just Venmo you the retainer?” If a potential client hasn’t asked you that question yet, just wait. So many people never write a check today. But many use Cash apps instead of credit cards. Is it appropriate and ethical to accept fee payment by cash app? Is there a difference when it is a retainer versus a payment on a bill for services? Can you ethically attach a payment app to your trust account to facilitate receiving retainers?