That depends where you are at in your level of fitness. If you are just getting started then you are correct for many reasons. I'm 61 and have been a gym rat for a long time. I do massive amounts of exercise and I love it - and I'm quite healthy. Yes, you do need to protect your joints. This becomes more critical as you get older. Maintain good form. But my typical work out is two hours of intense weight training followed by a 5K run or 25 minutes of swimming. I do this 3 or 4 times a week. That's what I consider "fun". But I spent well over a decade working up to this.
Unfortunately, I sit in front of the tube all day which is not conducive to exercise. I do get up and walk and walk in the evenings.
I took a major hit when I had back problems a few years back. Had the surgery but never really recovered completely. No drugs which is a huge plus.
I used to love my bike rides. Rode all over the city. The bike trails and walking paths are connected all over the city. You can ride your bike 80 miles in one direction all staying on walking paths. And I'd hike the foothills and open-space in the area. There was a very nice trail right at the base of the mountains and was 7 miles. I'd load up my day pack.