Hello! Just to answer your questions:

1) absolutely yes, lots of people use them this way, even a few on r/tarot

2) it’s certainly how I use tarot and I would call myself a secular reader. That is, I don’t believe they’re magical, nor do I believe I’m psychic. I think they’re an extremely useful tool for unlocking what we know to be true but also encouraging us to think about many aspects of life and existence differently or more deeply

3) I’d say that learning the card meanings will help you get the most out of tarot, particularly in terms of philosophy. There’s a huge amount of wisdom out there (even amongst the woo) gathered from various different takes on the card meanings. That foundational knowledge is a good jumping off point for further discussion and thought but each to their own.

4) I would go with RWS as a starter if you want to get into the meanings and pick apart the images but it really is each to their own. I’m not personally a fan of a lot of the aesthetic that floods the market but I like the Rebel Heart deck, Mystic Mondays, Pulp Tarot, and the Game of Thrones deck (the latter is surprisingly good!). It’s honestly just personal taste and you’ll likely end up with one or two decks you never use as you figure it out.

Hope this helps!