I like this approach. Everything it does can be achieved by OBS with a couple of plugins, but this is a very user-friendly packaging of great looking presets: use cases over technology. Also, super fun name.
It's kind of bad for discovery.
Still, it's blowing up.
I made the opposite conclusion from your anecdote.
> it took a long explanation to describe
This strikes me as a good thing for this sort of product.
As someone who has done quite a bit of pretty successful product and company naming, the choice "Mmhmm" has quite a few negative aspects which I consider to be fairly important, though not requirements.
* Hard to only hear first then spell correctly.
* Hard to only read first then pronounce confidently.
* Hard to find when searched, even in combination with other likely terms (e.g. video, streaming, app).
* Can be confusing when introduced as a new-ish term in conversation.
* Such a notably 'unique' name can trigger discussion about the name itself which can lead to distraction or delay in communicating the product's value prop (as seen in the first third of their own intro video).
* Even for those who may find it "clever" or "cute" initially, it will likely become annoying over time for those in the company as well as the company's most valuable stakeholders.
Against that, the upsides don't appear (IMHO) to be a good trade-off.
* Short
* Quick to say
* Unique
* Memorable (at least on the verbal dimension, if not written)
* The domain was apparently affordable.