I've actually eventually gotten pretty quick with an onscreen keyboard, but I still miss the sliders. They at least made cases that would add them to popular models for a few years after there were really any noteworthy models that came with it built-in, but it's still absurd to me that physical keyboards haven't been a thing on phones for so long.
most stores here in sweden have hand scanners you can use as a member, and some of them let you write shopping lists and have it show up on the scanner, which can be put into a holder on your cart.
that's sufficiently useful that i'd use it if i did stuff like weekly shopping, alas i shop daily and thus never buy more than 10 things at a time so fart noises to that.
I just use my smartwatch for this now. It's a lot easier to simply dictate your list to your watch, than to carry around a pen and pad that I'm just going to lose on my way to the store.
slide out keyboards are a niche that's just barely hanging on. there's the F(x)tec Pro, and the Cosmo Communicator, at least. seems they're more in style for handheld game consoles: i'm crossing my fingers ASUS or one of the other mobile-phone gaming manufacturers will notice that and cash in.