John, put aside all the tweaking talk, you just answered your own question here.
You don’t need it for the main system so don’t get one.
You do need one for the bedroom so get one.
Don’t spend any more time thinking about it.
The differences are very small, if you want to invest any more time in improving the system, invest in speakers and the room, maybe through DSP room correction. Everybody agrees this has much bigger impact than tweaking the digital bits.