My estimate is that trying to use a soft keyboard drops my effective intelligence by at least half.

Typing is slower and far more error-prone. I'm staring at the keyboard rather than what I've typed, so if there's an error, I don't see it as it occurs (which would enable me to correct it immediately), and navigation is exctremely imprecise. My error / typo rate with a software keyboard is through the roof.

With a keyboard, all of that is much more fluid, and I can focus on what I'm actually trying to say. Being able to toggle between apps and access application hotkeys is another huge bonus.

Downside is that many applications literally don't know what the fuck to do with a keyboard. Apparently keyboard entry is not a consistent low-level Android feature.

- The Pocketbook e-book reader interprets spaces when writing notes or search expressions as "page scroll" events. This is always delightful.

- The Mozilla Pocket app loses focus on each motherlovin' keystroke when entering tags. My enthusiasm for this behaviour is utterly without bounds.

- Depending on the keyboard and perhaps Android version, input of escape (hullo, vim), function keys, and other modifier keys ... is variable ... with Termux. The Logitech keyboard largely functions as advertised, though there are some workarounds required for function key usage (say, with Midnight Commander).

I'm sure you'll discover other fun surprises in your own preferred apps / workflow.

That it's easier to write longer pieces with a keyboard may or may not be a feature, though on balance I'd consider it a plus.

Using Termux or remotely accessing a Linux / *nix system with a real keyboard is also a huge improvement over soft keyboards. Termux (Linux userland available through F-Droid) remains the one thing on Android that does not precisely suck.