I have a cards for Dekalb County, GA and Fulton county, GA - I live in one and work at an educational institution in the other, so I can have both. I also work at a university library.
My main electronic use from the public library is ebooks through Overdrive, through their recently released Libby app. Most of the databases the PLs have are available to me through work as well, so I’m more likely to use my work login for those.
I’ve had a library card in every place I’ve ever lived since I was a kid (lemme see… seven towns or cities by now, I think). I carry my card in my wallet but don’t need it to borrow or reserve things online, since I have an account set up. In the past year I’ve begun downloading audiobooks to my iPhone - very convenient, IF the book is available. It’s annoying to have to wait for an audiobook - it’s electronic, can’t they just zip it over to me? - but I guess the library has only so many “copies” and can’t just make more due to licensing agreements with publishers.
I borrow many more books from the library than I buy to fill my already-overcrowded shelves. I make use of interlibrary loan several times a year for more obscure stuff, and it’s rare that either my county or city libraries (both quite good) can’t find things for me.