Personally, I find that completely uninformative. Others find it helpful and I won't deny their experience, but I find that no more convincing that proper arguments about the 3 door version.

My variant was not intended to assist explaining the original, it's a variant intended to make people think again. It often exposes non-understanding in those who will blindly and automatically say "Switch".

Here's another variant. 12 doors, I let you choose 3. I then open 4, leaving your chosen 3 and 5 others.

I let you keep your original choice, or give them up to choose only one of the others. Should you switch now?

No, In that

P(3/12) = 25%

The remaining doors have 75% probability and choosing 1/5 only gives you 15% chance of winning.

Correct.

Explaining that to muggles, though, is non-trivial.