I had built a similar remote many years ago for my mother-in-law so she could press a button and send commands to several devices at a time. It worked well but I see you opted to do the same thing by having a power switch to turn the remote on and off. One of the things that I've thought would have made the project better is if it was like a true remote and did not need to be powered off to allow the battery to last a long time. It looks like you did some things to make it lower power but I assume the CR2032 battery would only last a couple of days, if that, without being switched off.

I was also looking into creating a Roku remote replacement so you can actually key in the channel you want to watch rather than using the up/down channel buttons but it appears that Roku does not have IR codes to actually input a channel directly. This is a source of frustration with folks who watch over the air TV with their Roku TVs.

Measuring the current draw in standby to be in the range of ~30uA, I calculated the battery should last at least a year with the power switched on. I've still got some peripherals turned on though so it's not the lowest power state it could achieve (iirc the atmega328p can go down to something like 4uA). I really only added the switch for even longer term storage or just to prevent it from wasting power while in the pocket if a button is accidentally pressed.