I like to hold the zapper for a second so it brings up custom amounts and the ability to sign it with a note too 
Discussion
Yes, I reverse engineered the private zaps back when they weren't defined anywhere so Amethyst was compatible with private zaps from Damus in the early days. I think they are potentially the only 2 clients up to this day if I didn't miss anything (DVMs also understand private zaps, but these are not clients)