I was a little worried about this originally as well. In my case, for some inexplicable reason, my wife hasn't complained at all about a combination of traditional toggle switches and newer decora style switches. When I do add a smart decora style switch to a box, I replace all of the dumb switches with new inexpensive dumb decora switches as well. I am also slowly switching the house from old almond switches to white switches (which she prefers!). The Lutron Pico's fit right in with the decora switches, which she prefers to handheld remotes or touchscreens.
If you survey the smart switch market, decora style really is where the momentum is in the USA. No reason to fight against the mainstream. 
