I had a gym membership for several years and spent 2-3 sessions a week on an exercise bike in the winter. In the summer I rarely visited it at all. Winter 2017 I cancelled the gym and bought a turbo, expecting I'd do more having it at home. In reality I did less and entered 2018 quite unfit.
Last winter I bought a modest smart trainer a tacx flux. First one broke and I got a replacement from Halfords. I got a zwift subscription and it was a revelation. I've never done structured training before, I settled down to quite a disciplined routine, increased my ftp by 40 watts or so. The surprising thing was the improvements from not going flat out. My comfort zone outdoors is 30-50 miles as fast as I can. I rarely do more than an hour and a half, with some of my workouts less than an hour. I didn't think much of the zwift training plans, but I've designed my own workouts. I've tried some of the races, but didn't take to them. However just riding a course, digging deep on the hill climbs and really going for the sprints gives a good varied workout.
My children used to spend a lot of time playing Mario Kart. I tried occasionally, but never took to it, partly because I wasn't as good as them. Zwift is a bit like Mario Kart for bikes, with some of the same computer game elements, the cartoonish look but also the knowledge it is other real people and not a computer you are playing with / against.