Personally I think they are fantastic.
Just throw them in your bag or pocket and off you go. The newer ones are getting bigger but still a lot less annoying than the usual car key.
I don’t drive every day so see no need to lug around a stack of useless keys.
And both of my Renault keys have a slot so you can tie them onto something if required.
I got one a while back for another brand of car. I (honestly) can't remember what it was now, but it didn't start with T. I would remember that.
Oops. Spoke too soon. Just logged out to see what would happen and a lexus ad appeared...