Cf. prior comment re: "I'm a lazy geek". Most humans are .You can always put a different card in. What's wrong with a collection of cards?
I want to listen to my music - all of it - whenever I want. I do not want to manage a library of SD cards and swap them in and out while I'm walking down 8th Avenue or I'm busy working. By the same argument, I could still listen to my 1,000+ CDs, but storing them all and finding the disc I want and putting it in a player to get to the track or two I'm jonesing for is a crapload of work. I'd rather have them all digitized on a hard drive on my server (or an SD card in my DAP).
The high resolution music I've collected (250-300 albums) in the last five years is well over 1TB now. The CDs I collected starting in 1984 (>1,000 albums) are roughly half of that - ripped at redbook in FLAC. So in five years my music collection has TRIPLED in size. I hope it won't triple again by 2025 - then I'm even more toasted! Even with two SD slots!
Doody