Title.
Well all classes effect your GPA so yes they do matter.
Even though colleges may not stress upon them when looking at your resume, classes like art and gym can be a great way to bring your GPA up.
Yes they matter. I wish I took more of these classes in high school
Yes they do matter, they bring up your GPA and they’re usually a graduation requirement.
Yes.
Unfortunately in our weighted system, these classes tend to have a negative effect on a student’s GPA. (Art, P.E., sports, music 4.0/ vs. Honors= 4.5 & AP= 5.0) This can drop a student’s class rank. 
^Unless the high school uses weighted class rank.
Counts for admission = gym no, art yes (in fact art is a requirement for California universities, they won’t even consider your application if you don’t have one year of it - that includes band, music, Ap art history, visual art, photography…)
Matters to a good life = yes, both (as long as you exercise enough and can understand how to read a painting or how to express yourself through an artistic medium, your adult life will be enriched and you’ll enjoy things a lot more when you start travelling, especially abroad.)
yeah don’t screw up because your weighted and unweighted gpa from free points will go down.
My school offers exemption from gym if you complete 2 seasons of any school sports, otherwise it’s a graduation requirement. Check and see if your school offers exemption because if it does, it won’t affect your GPA.
Of course (though gym is arguably less so if we’re just talking about college admissions). Art is most definitely important both for college admissions and life in general, and as someone who loves the arts, I am very very happy that I took music and art classes all throughout high school. You won’t get those chances or many of the resources that schools offer for the arts after you leave formal education.
When I said this I meant are they calculated into GPA?
For your HS GPA, it depends on the HS. If the college recalculates your GPA, they will often, but not always, not include non-core courses like art, music, shop, etc.
As far as I know, classes like art and music are factored in by colleges, but not classes/periods where you get a grade for band, choir, soccer, yearbook…