[Houndoom's tail gave that gentle swaying wag, and there may have been a little nose-to-nose boop of greeting for Tepid from him. Litten played just a little disinterest, but she still sniffed and a gentle paw out in offer for return.]

You could say that- in my world the pokémon known as Rotom are used within phones, happily living in them. It keeps the phone charged at all times, and Rotom is very helpful whenever by keeping the use mostly hands free.

They are free to leave if they wished to. [As proven with Turo's Rotom leaving his phone out of boredom some months ago.]

It is a technology developed within the last several years, and in another region I know it started with Rotoms being used with pokédex to better help trainers.