I'm all for making use of libraries and, before I got into the Kindle, I was a heavy library user.
I do belong to an overdrive ebook library and use it mainly for audiobooks because Kindle doesn't natively support library books.
But, part of the fun for me with all this is that I love to build up a collection of books. I also enjoy cataloging those books using Calibre. So library books alone would never be enough for me - I like the sense of ownership. And, unlike tree-books, I can easily store thousands of ebooks with no space issues.
It's about finding what works for you. If library books satisfy your reading completely - great. If not there are plenty of alternatives.
Two things I will always spend my spare money on - gadgets and books. And I never consider either a waste because of the enjoyment I get.
Happy reading OP