Oh, you can touch type emoji and symbols today. There are all sorts of interesting Input Method Editors (IMEs) for them. Since Windows 10 there's one by default in Windows if you type Win+. or Win+; (whichever you prefer). You can type and it will filter the emoji by name. It's not quite as nice for mathematical symbol entry, but it does include them (on the tab labeled with an Omega) and is still better than many other input methods for them. macOS has a similar out-of-the-box IME (Control+Command+Space), though it differs on the amount of math symbol support. Linux's most used IME subsystem `ibus` (specifically `ibus-emoji`) if correctly setup should also by default provide an experience for emoji (Super+. like Windows). There are third-party ones as well for most platforms.
Emoji is not just for tap-typing/swipe-typing mobile users. (Also, I think it is really handy as developer to learn your local emoji IME: including emoji in test data is really handy for checking unicode safety in your applications and regularly using any IME at all while in your applications helps you test some accessibility issues that might affect users that must use an IME for there language such as CJK languages and Braille writers and more. English software developers get to overlook a lot of how languages around the world work and can easily break accessibility needs with bad assumptions and it is great that emoji are a grand field leveling tool to bring those experiences to us English speaking developers in a way we can easily "read"/"write".)
I meant "brevity at all costs" languages like J and Uiua strike me as the kind of contraptions that people who can't type fast would come up with. I speak from experience. I had a coworker who would write absolutely cryptic code and one day we were working together and I noticed he was typing painfully slow, and then it all clicked.
I'm well aware it's possible to type eg Chinese rapidly, and I use the Windows emoji entry keyboard quite often.
I see these languages as resembling classic mathematical notation as much or more than I see them as "lazy typist" languages. To be fair, some of classic mathematics notation was designed to be easy to write on blackboards, but that's still very different from being easy to type.
