there are things that can too easily expand to fill all of your time while only being a certain level of better than baseline. If you want to feel even better than just browsing the internet you need to not allow it to fill all your time. I also value doing DIFFERENT things, though not everyone does. It's easier to do different activities (ie the threshold cost to starting them, which is usually the biggest emotional price you pay) if you're NOT doing something fairly engrossing already.

if your base state is 0 hedons (neutral) an hour, internet is 5 hedons an hour, and going to go out dancing is maybe 1 hedon during travel time and 20 while doing it, it's easier to go dancing if you're deliberately cutting off your internet time, because you don't have to spend -4 hedons to get out of the house.

Another concern is when people care about things other than direct hedons. If you have goals other than enjoying your time, then allowing internet to take up all your time sabotages those goals.