I like SD cards cause you can pop a 250 or 500 gb card into a device that might only have a 120gb storage to store music and media like movies or tv shows
I think it's especially usefully for someone who dosnt want proprietary apps like Spotify or YouTube music, to be able to play everything from disk
Mind you the 2Tb SSD I just bought for my pi is smaller then a deck of cards and could theoretically be plugged into my phone in my pocket and I could listen to music off of that I guess if I really didn't want YouTube music installed (I just installed grapheneOS for the first time 5 minutes ago, I'm on this board trying to figure out how I want to set it up) but the thing is I think I'm going to set up a user profile for my Gmail and YouTube and YouTube music and bank apps
And a removable battery is based, as long as there's no secondary battery inside the phone, knowing the device is 100% dead when you click off the battery is good for people tryna sneak around town 😉