I wired my house not to increase my internet speed, but the speed between devices in my house. I stream bluray rips, and regularly transfer files, and the latency and overhead of wifi connected devices causes problems and took up more of my time than I liked.
Wired, I can stream to multiple rooms and still use the net from my main box without any slow down and without any degradation in the stream quality.
But you're right, if you're in a single user situation, going wired isn't necessary.
My HTPC is wired in the office. I stream to 3 rooms, my wife is usually on Plex or Netflix or watching a game with me on League Pass or local cable.
When I am downloading something on the desktop and maxing out my connection, I tether my phone if I'm trying to watch something online, play a game or just get online.
Unlimited LTE at the crib comes in handy