One is the "smart" part of my smart TV. One powers my hifi. One connects my non-networked printer to the network.

One is an NTP server which gets the time from GPS, although that one will probably be retired soon, internet time works fine.

I used to have one inside a MAME cabinet but I upgraded it to a "real" PC because the Pi isn't really powerful enough for modern versions of MAME.

What do you use for the smartTV (distro)? And do the big streaming players work happily?

I use LibreELEC. I don't watch streaming TV, I have traditional cable and an HDHomeRun Prime box which acts as a cable-ethernet interface, which Kodi will happily connect to.