That aside, in terms of worrying about your mic picking up other people's voices and the voice dictation getting confused, most dedicated microphones these days (i.e. not ones that are built into your phone's headphones), are pretty good at background noise reduction.
I've not used the one OP recommends - I'd never have considered a table based mic like that before - but the noise reduction on the Plantronics Blackwire 3215 headset I use is so good that if I move the mic boom a few inches up or down away from my mouth, people can't really hear me on calls. It's superb at getting rid of background noises, and if somebody else was in my home office using voice dictation it would not be picked up by my headset.
I work mostly from home, so I'm interested in this as a programming method to see how or if it changes the way I approach it as work.
1. Cheapest is probably a USB dynamic mic of some kind.
2. Next is a Stenomask at around $250
3. A lot of folks swear by the DPA d:fine cardioid, which is $800-1300 including an interface. There’s also cardioid shirt worn lavalier I’m interested in trying sometime, which is the same interface but the mic is $150 cheaper ($650 -> $500)
If you’re worried about other people hearing you, your options include an isolated area, playing noise (white noise or music?), or using a StenoMask, which blocks sound in both directions.
Remember in the US your employer is required under the ADA to provide “reasonable accommodations” for disability, which may include a private working space, pair programming, or letting you work from home more often.