The same reason people use adblockers, get around news article paywalls, and/or pirate. Because they can, and don't see ethical issues with it.
> if everyone were to start using Vanced overnight, YouTube wouldn't be able to justify staying up indefinitely.
How likely is this though? For example despite adblockers already being widely available, it seems that a significant portion of internet users if not most don't actually use them.
Having worked on a largely ad-supported website in the early '10s, I can definitely say the rise of ad blockers had a meaningful impact on ad revenue. I didn't mind this at all, I much preferred the product investing more effort in making the subscription that removed ads have attractive features, but if users had a way to also get all of the subscription features without paying, I don't think the business would have been able to sustain itself.
> if everyone were to start using Vanced overnight, YouTube wouldn't be able to justify staying up indefinitely.
How likely is this though? For example despite adblockers already being widely available, it seems that a significant portion of internet users if not most don't actually use them.