Televisions and home theaters need remotes, our hi-fi systems do not.
For those ancient enough to remember when equipment did not have remotes, we solved the problem of volume adjustment in the same way we made it easy to play a record. The preamp and turntable were next to us. No system worth its salt was set up away from us. We kept it simple. A table to the side of the couch or in front of us had the turntable and preamplifier at the handy. It was a perfect setup.
Televisions changed everything because they couldn't be positioned within arm's reach. So remotes were invented, first using ultrasound with clickers, later with infrared as most are today. Then, a marketing nerd decided what's good for TV ought to be good for our stereos, despite the fact it was not only unnecessary but injurious to their design and performance.
Frankly, I never got over it. Our equipment is now far from us for one reason. The remote control feature permits it—almost demands it. Because we can, we do.
Where our kit once had clean sounding mechanical switches and decent pots, we had to resort to worse sounding relays and electronic volume controls—or complex motorized pots—to mimic that which made sense on televisions. The whole world has gone remote control and what manufacturer doesn't feel obligated to include it?
After all, we've now permanently rearranged our equipment and living spaces to accommodate the convenience of a remote, rather than the other way around. Ahh well.
So, what does adding remote control mean to a piece of equipment? We'll get technical tomorrow.