Contactless seems to take longer IME
To speed boarding at Leeds bus station during daytime Transdev normally have member of staff selling tickets but they still appear to need to be checked by the driver, the quickest is usually someone holding a pass or rover ticket but its amazing how difficult operators typically make finding the details of such. My local operator use to sell a day ticket through its mobile app that worked for a full 24 hours which was great when I broke my collarbone. Somehow managed to wrangle Friday afternoon visits to the hospital, thereafter a walk to Sainsbury's to do some shopping and then, typically around quarter past four starting the ticket which meant I had the use of it for most of Saturday daytime. The app has now had what seems to be a downgrade as the full 24 hour mobile ticket ceased.