Aside from the pragmatic reasons, I think it's a good idea to separate out cardio, muscle-building, and flexibility into its own separate categories, and ensure you consistently dabble in each. Obviously there can be are overlaps, but this taxonomy ensures a good balance.

I don't see this as a binary thing. Legally we tend to draw a clear line between child and adult for pragmatic purposes, but I don't think my responsibility of intent disappears just because someone hits a magical number. I have steered clear of various gambling / "gaming" jobs which have had silly high salaries as a result; I don't in any way want to participate in things which are meant to play the weak points of the human psyche like a harp, for profit.

To be fair, this topic seems to be quite divisive, and seems like something that definitely should be discussed during an interview. Who is right and wrong is one thing, but you likely don't want to be working for a company who has an incompatible take on this topic to you.

I find the chess comment fairly weak; while chess is a "perfect information" game (in that you have full information about every piece on the board), at every level that chess is played at there will be unknowns about the player you are facing.

At lower levels, you can certainly play sub min-maxed moves that are more likely to confuse or pressure a weaker opponent. You could call these bluffs. Opening theory is also a wonderful game, you're essentially playing a game of "let's bet that you haven't prepared this particular set of lines as well as I have" with the opponent. The same thing goes for game styles, open vs closed, etc.

Last but not least, playing a perfect game of chess is so far out of the realm of possibility for humans, that the entire "there's always a correct move" is completely irrelevant. We are now at a point where 7-piece endgames have been completely solved, and it involves 4.2×10^14 positions. Good luck memorizing that, and the scaling from there on out is not pretty.

In this sense, chess occupies a very interesting spot; somewhat calculatable for a human (and yes, tactics dominate up to say 2000 ELO), but there's plenty of room for creativity and strategy also. It's also played at an insanely high level, which makes it a worthwhile challenge and time investment. What it does NOT have is randomness. I often wonder what the competitive landscape of a chess variant involving some randomness would look like, or if it would fundamentally change the nature of the game.

I completely agree, it's fantastic both for general fitness, and as a way of exploring. I do this on a smaller scale on a daily basis, walking the 8-10 km route to or from my work (when we have office days). This is walkable in about 1.5 hours, public transport would get me home in around 45 minutes, so I am not really investing much extra time. Varying the route slightly keeps things interesting, and you get a surprising variety with small (1 to 2 street) changes.

Another favourite of mine is cycling around a neighbourhood to get to know it; you get a totally different feel for things than from a car - things typically go by slower, and you are somehow just far more able to observe things.