Throwing my experience with meditation down in here. I said almost exactly the same thing in another post recently. I should preface this with saying that while I'm attracted to Zen Buddhism, and ended up getting an accidental minor in east asian religious studies way back when, I don't meditate
because of Zen Buddhism (though obviously I acknowledge a lot of the history there).
I fairly consistently meditate. I don't spend more than five or ten minutes in any given setting, so you might not consider me a hard core meditator, but I do feel that it's provided me with some positive mental tools. I'm going to focus on the ones that aren't necessarily related to long term average increases in objective health and wellbeing and more on a subjective perception that I have new cognitive strategies to deal with certain situations.
As an example, I used to be pretty anxious about falling asleep, and I think it caused it to be more difficult to fall asleep. Some of the insight meditation practices helped me deal with the anxiety feedback loop. It wasn't something crazy or mystical; I mostly just learned how to effectively stop thinking about something, or at least stop focussing on something. Ordinarily trying to stop thinking about something had led to a nasty loop. I can't sleep, so I get anxious, the anxiety makes it harder to sleep, which makes me more anxious.
The meditation got me more comfortable with just sitting, for one, and secondly it helped me learn to acknowledge a thought, and "let go" of it. Eventually I got to a point where I wouldn't be able to sleep, but whenever a thought that would provoke anxiety popped up, it would just sort of pass by, and I never actually felt the emotional reaction.
Honestly, I don't think I fall asleep any faster (again none of this is quantitative data), but I do find that I just don't care anymore because the anxiety isn't there. It's not the effect I expected when I started meditating, but it's just as, if not more effective.
I continue with it because it's pretty easy to carve out five or ten minutes here and there. I have no idea if it's causing any long term health benefits, nor does it really matter to me. Subjectively I feel more relaxed right after I meditate, but that's about it. Honestly, I'd keep doing it just because it feels nice. I don't do any crazy postures or full lotus, or anything like that; maybe there's something I'm missing out on, but I do plan on continuing the practice as I perform it. I try to keep my reasons for that as subjectively tangible and non religious/spiritual as possible.
Side Note: The book "The Wisdom of Insecurity" is an interesting Alan Watts book. I like Watts work but like anything, I have a tendency to read things looking for what's wrong with what the author is saying. Eventually I learned to more actively look for what's useful instead, which I think is helpful with that kind of book, otherwise I end up in this endless cycle of critique, which is fun but doesn't really get me anywhere. (I'm not saying don't do critical analysis; more just be aware that there can be value in imperfect works)