My sibling (using Debian Testing) had wrist RSI this summer and we tried to set up Simon Listens (the previous version; 0.4 looks from the release notes like it's improving). We are both Linux nerds. We were not able to get it to do anything useful after a few days of work, and I estimated a 50-50 chance that working harder on it would help[1]. I did not find any other FOSS speech-to-text that I could get working either. (FOSS Linux text-to-speech is much better; e.g. Orca is good.) We did not try any commercial products; Dragon Naturally Speaking is the only one I know of having a good reputation but it is Windows-based. Also, it's hard to integrate well into the Linux stack without being FOSS. A list of products we looked at: https://en.wikipedia.org/wiki/Speech_recognition_in_Linux

[1] Issues with compiling, dependencies, figuring out the conceptual model Simon Listens uses, trying to figure out whether Simon-not-doing-anything was because we miscompiled it, or audio input, or incompatible dep versions or misconfigured deps, or us just doing the wrong thing because the English documentation wasn't super thorough... Imagine setting up Apache, MySQL and PHP if there weren't a billion tutorials online, you'd never used Apache, and MySQL wasn't compatible with your GCC unless you pulled the git version and hoped you didn't get confused by dev-version-only bugs.