some people like worrying in the present to avoid potentially worrying in the future.

how is this a good trade?

Well it all depends if you're worrying about something you can solve now, or not.

If you worry and find a way to solve it now, you don't have to worry about it anymore.

If you can't fix it now, worrying is indeed wasting your time and energy unnecessarily

What if you solve something and it never happens. 

What if you solve something and it happens, but in a different way than you solved. 

Many what ifs ....