If you're curious why asking for subscribers is so prevalent, I recommend taking a look at this Twitter thread (https://twitter.com/stalman/status/1369082704138883073) that describes the before and after effects of asking for subscribers, here's a quote: "Just the subs that came directly from the video page were 5x what they are on similar size videos".

I also recommend this blog post about the best way to ask for subscribers: https://reneritchie.net/how-to-get-subscribers-on-youtube-ev...

I've never done any of these things, and I'm not sure I have the stomach for it, but I consider it required knowledge for anyone with any interest in leveraging online attention.