It really depends on what you want to do. If you’re trying to build muscle, lifting weights and a little bit of cardio will make you strong and feel just generally better (less mental fog, have more energy, etc). You can generally get a good deal of the benefits if you’re just starting out at home, provided you are actually being consistent with your workouts. Workout clothes are much more comfortable than just wearing a pair of jeans and working out, plus they won’t chafe if you get them wet from your sweat. A lot of the reason I have a gym membership is that it provides an incentive to actually get my money’s worth by going to the gym (I am rather cheap), thus I’m less likely to not workout. I think we all remember how awful gym time at school was, but a paid for gym is a much better environment, as you can go take a shower after rather than having to be sweaty in your clothes for the rest of the day, or even just working out at home with the opportunity to shower after sweating.
The theory I’ve heard is that is exactly why they are doing it now, as apple has set the “side loading” precedent in the EU.