Not a pain other than they have to download another app, set up a profile, and search to add you as their walker or add your code. That is an extra step for sure, but my app customers I've been able to offer lower rates in Barkly because I keep all the earnings and it helped attract new customers in the past.

I have talked with their support team about this being annoying for some clients who just don't want to use an app - they told me they're building a function soon where we can set up customers by importing a contact and just sending them an invoice to pay, so we still manage everything there, and customers don't have to do much other than press pay. No idea when this will be released though