Is it worth it to apply to schools you can't afford?

No but that doesn’t mean you have to give up getting into a “dream” school - you just have to open your dreams to include the large number of schools that aren’t UCLA, UCSD etc. What makes those a dream? Location? Size? Majors? Figure out what you want in a college and then find out what schools in-state or out of state/private that will offer you need-based or merit aid will meet those requirements. Don’t bother applying to schools who absolutely won’t give you the aid you need to attend, it’s a waste of your time, energy and dreams.