It's probably for safety. Mine has a "hard" switch on it, which I use to turn it off- if it didn't have that, I'd unplug it. Keeps my kids from having accidents.
I just got an extra remote control outlet adapter for mine. Hit the button and it’s essentially unplugged. Use the same thing for one of my trainer fans that sits on the floor that I couldn’t easily turn on after getting warmed up.
I have toddlers so I tend to turn mine off and unplug it. We also have a good bit of summer thunderstorms here so added protection to unplug it there as well.
We've had a Nordictrack 2950 for a year or so, and have never turned it off or unplugged it. The iFit SW takes a few minutes to boot up, so that would be annoying to have to go through every time. I've never had an issue, but then again our kids are now teenagers so they presumably have at least a minimal survival instinct.
and ifit does take a while to boot up, but oh well.
i like the ifit feature of following someone on a trail and the incline/decline happening as i go. i do turn off the sound. i do not want someone talking to me when i run.
My favorite feature is being able to map a run in iFit (using the google maps street view) and then run that course with the treadmill changing the elevation profile to match and showing the street view images stream on the display. I "pre-ran" the 70.3 CdA course several times before race day this way and felt like I had a good sense of the course on race day.