I've seen this in several houses now and I don't understand it: a wall plate with one ethernet and two coax jacks.

Nevermind that I think it should be the other way around, what on earth could I need two coax jacks in every room for? In my house there are five rooms with coax, which would require a 10-way splitter which is uncommon and from what I can tell online is generally frowned upon (8-way seems to be the recommended maximum for things like Fios).

I'm going to be terminating cables in a very large house next week, and the cabling installers put two coax lines in every room of this house - 13 rooms! So there are 26 coax cables coming back to their mechanical room. That's insane, right? What the heck is that even for?