The problem arises when an emergency occurs, or when you actually do go on vacation; or when you are otherwise hindered from accessing the internet. Although, I have rarely actually used my vacation time, I find it beneficial in such situations; and I am glad not to be penalized with a loss simply because the electricity went out or that I couldn't make it to the library, or a hundred other things that might keep someone from being able to make their move.
We sign up for these games because we WANT to play them, NOT because we want to annoy people whom we've never even met by making them wait.
Joke.
But it would be very nice if vacation was abolished on chess.com. Because you know its so frustrating when your opponent in a daily game, for example 3 days, after full 3days goes on vacation for 8 weeks😡