When I first started, I cut my teeth on Match Play..30 second clock. I play fast and 30 secs was plenty of time for me. I did receive a lot of complaints from more senior players about the short time.
As I consider this a social game, I moved to 60 secs, and now to 90 secs for Alternate. Lots of time to chat, etc.
I am still fairly quick, and it does bother me a bit when players take 80 secs to hit a 5 foot putt...but whatever.
IMO, 15 secs may be a bit short to become a popular selection.
ct.