This isn't a fashion show, but the form factor is still something that matters. In the case of a standing mic, you'll be staring at it every time you're sitting at your desk—and attachable mics need to make sure they aren't too distracting either.
A mic's form factor can also play a role in how adaptable it is, as you'll need to make space for it. We used every mic in multiple settings with different PCs, keyboards, and monitors, getting a feel for how they looked and performed in each environment. As a streamer, your mic will also be in view for your audience, so its appearance is relevant.