Push to talk is the only way to ensure that no sound will leak in your environment, specially when you have 2 or more ppl working from home office in the same room.

Competitive tools like Teamflow, also have a push to talk button. Super nice to have, improves quality of life in the tool.

It would be great if this works even if the app is not selected.

The space bar would be a great choice for the push-to-talk key.