That said I can say that having depression (and a bit of PTSD) is way more of a hell without the weed to take my mind off it. And even if it's just playing a video game for 6 hours (rimworld is my current 2nd drug) that's far more active and engaging than my typical super depressed not leaving my bed state.
I also think bettering yourself and being a success isn't a one-size-fits-all package. I have a friend who smoked so much damn weed it's a wonder they have any brains left. They learned to play league of legends 10+ hours a day sometimes while high as a kite. They're now making multiple times the money streaming on twitch than they ever would've with any job they would be qualified for. They're the happiest they've ever been, met their SO through twitch, and are living the good life all by ignoring the advice being given here.
All those things feel AMAZING while high, even if the banal things feel way better than sober. Cannabis doesn't just somehow discriminate to make only unproductive activities feel better.
I personally reached the conclusion to start seriously self-learning coding while stoned out of my mind and would furiously code in my room while stoned out of my mind. Now, about seven years later, I have a good career as a developer and still get stoned silly every night.
We really need to look at society and ask why people are looking for a way out instead of a way in, but I guess it's easier to blame weed.
Some of the unhappiest people I know obsess over optimizing every second to be productive
We're not all Elon Musk, working 90 hours a week and always starting up a new start up. Banality will ensure we don't burn out before we're 40.
Also Bill Gates, Steve Jobs, Richard Feynman etc. (of course that doesn't prove anything - but it helps keeping things in proportion)
Banal: Overeating/overdrinking/overconsuming, sitting around, reading reddit/HN for hours, playing video games or twitch.
Not banal: Challenging yourself to new activities or hobbies that require skill. Seeing the world, interacting with other people IRL. Learning (new topics, reading, etc). Building things. Getting out of your comfort zone.
Essentially, being passive/not learning/not engaging vs. learning/challenging oneself and trying to be more than you are.