I use the button, but only in situations where i know theres no worry if i leave the key in by accident. Such as when i'll be back on the bike within a short time and theres no option not to. Say if i stop for gas, or a fast food place, etc. Obviously you aren't gonna stop for a burger then walk homne and leave you bike there ! (at least no when sober:))
But when i stop in a place where i have the intention or option to stay off the bike for any length of time i always reach for the key. I wish triumph hadn't cut some corners on these bikes, and a ignition switch located below the seat is one of them. Stupid place to put it ! (but cost effective i'm sure.