@varx @eniko

It often isn't faster. I can't find it, but about 20 years ago I read a paper that did exactly that experiment. They set up voice controls that were really just a person doing the thing for you. They had one group do the tasks using conventional GUIs and the other do the command via the voice command. They subtracted out the time the assistant spent working in the second case. It was still both slower and more error-prone for most tasks. The outliers were very simple things.

Watch any Star Trek episode where someone talks to the computer and listen carefully to what they ask. Aside from Captain 'I don't know how to configure my replicator presets' Picard asking for 'Tea, Earl Grey, Hot', pretty much everything is so ambiguous that it works only because there's a script writer and not a computer deciding what Majel Barrett says.