Who uses one? Do they require a Cat 5 cable? How many people's
schedule can you set the temps for?

My sister and her two kids moved in with me.

My nephew is in school and it would be nice to warm the house in the
morning for him, but his come home time is different. He has a smart
phone and enough sense to use it.

My niece has a pretty regular work schedule. She also has a smart
phone and also enough sense to use it.

My sister doesn't have a smart phone and wouldn't know how to turn one
on if she had one. Just kidding, but she can barely run the two
remotes for the TV. Her schedule also changes the most. It would be
nice if it had a computer interface was brain dead easy.

My schedule is pretty much open 24/7.