Also, on a treadmill or stationary bike, if you get tired or just ain’t feeling it, you’re not 3 miles away from your house or car when you stop.

Sure you can run or bike outside but if you’re a few miles in and get hurt or too tired, you’re walking back.

I say you are missing the fun.

I bought carbide studded tires for my bicycle, and rode all winter back and forth to work. -20C doesn't feel cold once you start peddling, and you actually have to unzip layers to cool off.

The summers at 35C were hot, but the sweat and moving through the air cool you.

Very invigorating feeling compared to being in a gym.

Also, safety. There is a walk bike path near me and I prefer biking than stationary bikes, but not everyone has access to safe paths. Even the relatively safe path I use, I have maybe permanently injured my right wrist due to a fall caused by a dog jumping at me (he was just an excited sweetheart, but that didn't stop me flying off the bike). My sister also walks the path and has been chased by feral dogs, plus has to deal with creeps hitting on her. Lots of people walk with some sort of blunt instrument for safety, though personally I feel that's over the top.

While the only serious danger and injuries came from animals, that's still something you wouldn't have to worry about in a gym. The creeps... maybe, but still safer in most gyms than out in the open.

I get my exercise by cycling to work, sun or storm I have to get to work. So I'll be cycling 80km a week. That is before any extras like going to the shops or anything else.