I dislike subs for subs, because it's fundamentally dishonest.
They're rarely actually interested in reading my comic - and people actually reading my comic is part of why I make it and post it online; otherwise I could just let it sit unseen on my computer - and it puts the expectation on me to subscribe to a comic, regardless of its content, and I don't do that. I only subscribe to comics after I've read through all the existing pages, and I only stay subscribed because I read the comic.
I prefer to do my networking on social media or here on the forums, as it allows me to interact with people. Just subscribing to somebody's comic doesn't actually do anything for them. It's proper interaction and sharing that does things for people.