There are a limited number of hours in the day, and the more time wasted on things you'd rather not be doing is less time you're doing things that make you (and quite possibly others) happy.
There's no moral imperative to not waste time, of course, but I'd argue that increasing happiness in the world is never as trivial as you make it out to be.
Sometimes that means something as large as giving dying kids a last wish, sometimes that means something as small as providing a better/faster way to do something we all already did. How many people wasted time and energy shitty homegrown workarounds for file syncing before Dropbox showed up? How many shitty, stressful, overpriced cab rides did people have before Uber came along? How many relationships wouldn't have formed without things like Tinder and Grindr?
All "trivial" web applications, but all increased happiness in the world, one way or another.
What's your motivation for making this comment? Is it to increase happiness, knowledge, understanding, or any positive aspect of any piece of humanity? Or is it to take cheap potshots at people who aren't working on what you've arbitrarily decided is the base level of importance?
(And lest you ask: My motivation for this comment is to increase understanding - hopefully I can change your mind)