"as opposed to investing in businesses (making money for its own sake, I can see just nothing wrong with that)"
Supporting your ability to enjoy games, funding better ones, funding your existing one which will have plug pulled, and any arbitrary thing you want in life. Money is a tool to acquire, create, or continue to use other things. I'm endorsing getting enough of it to do that rather than collecting it for its own sake.
" Like mastering SMW2, for example?"
I don't know what SMW2 is. More like any creative hobby that lets you put things into existence or push your mind/body further. People that start these things are usually glad they did. Programming as a hobby can help you build better games, too. Or at least mod the ones you have. Or port them when they're EOL'd.
"going interesting places (sightseeing, such a productive activity)"
How did you find out about the game you like? Doing the same thing over and over that you did as a kid? Or meeting some new people, going to new sites, and so on?
" forming lasting bonds with people (lasting 80 years, tops)."
8-16x longer than most games. Especially when they go abandonware. The people tend to be more useful in other aspects of your life when facing challenges, too. Something you're not so good at or can't currently handle because life just dropped bombs on you. Easy for your friend. Plus, activates those other parts of the brain and its enjoyment that the games can't. I'm saying that from perspective of an anti-social person who usually doesn't want to maintain relationships but knows they led to many rewarding experiences.
"And what makes you think that playing games and doing any of those things are mutually exclusive, I might ask?"
I don't. You just asked what could be more meaningful. I thought that might be easier than people were making out given specific activities led to what you find to be most meaningful. And had people avoided those activities in favor of what you were doing, those things you love would never exist. Each thing you dismissed above had a hand in bringing it into existence. And for many people's happiness and some's economic benefit rather than one person. Turns out those same things did that for other products, services, causes, and so on. Seems doing or building them is more meaningful given the results are what so many, yourself included, find most meaningful. They amplify people's experiences.
"nowhere did I say my most meaningful moment "
Great pride, it was. Glad your more meaninful moment was something that might create more meaning for you and others, though. Maybe money, too, but I don't know much about the industry surrounding physics degrees. I'd imagine research, teaching, and support roles mainly. Example of support would be domain expertise for simulation software for physical phenomenon.
"more impact than others, though, with your book probably not existing unless someone stopped reading theirs for a while to create them with expectation of such impact. "
Now you're getting it...
"Rereading this makes me realize how misguided this point is."
Then lost it...
"I assume that it's all or nothing for you, indulge in a hobby and you are a leech on society, incapable of creation and mooching off the work of greater men. Lol."
A mix is best. If we look at introvert to extrovert ratio, even nature puts it at about 1 out of 4. The brain was meant to both consume and create. Society's structures give different rewards for each in different contexts. So, doing both in an number of contexts is likely most meaningful pursuit if your aiming for best experience as a human. Modified by differences in how people's brains work obviously with some getting no benefit from activities that benefit others.