You don't need to be active on HN to get into YC, so don't worry about that.
HN's purpose is to find and discuss stories that gratify intellectual curiosity. So to decide whether HN is for you, simply browse the front page for a few days and see if any stories there interest you. If they do, then there's a good chance you share interests with other people here.
The text-based design is on purpose. It focuses on the content and doesn't try to appeal to everybody. It's true, though, that HN can seem cryptic to new visitors. One needs to hang around long enough to let one's eyes adjust. I hope you'll do that before reaching a final verdict.
If you'd like to read more about the thinking behind HN, try:
https://news.ycombinator.com/newsguidelines.html
https://news.ycombinator.com/newswelcome.html
https://news.ycombinator.com/hackernews.html
http://www.paulgraham.com/hackernews.html