I mean the positive of a thought experiment is almost anyone can do it.

The negative is that most people don't have the scientific rigor to draw proper conclusions from their hypothesis, and may leave out very important data because it's outside their perspective to even consider.

Easily tainted, and not reproducible.

It's a good first step, and in the right setting can be very valuable.

Jim Bob musing on the nature of the universe is fine, until we start basing real world action on simple musings without actionable data.