Not 100% accurate - I was legal officer on my first command (not JAG but a collateral duty) - there are still evidentiary requuirements under the UCMJ for admitting evidence
You are correct, but I suggest that you read read the changes to the Manual for Courts Martial that occurred in 2017. The amount of discretion now allowed to a military judge is staggering.
As an example, he may deem something so important, or so overwhelming, or so truthful that he may allow admission even where a civilian court may not, based upon such issues as writ of warrant (4th), or fruit-of-the-poison-tree, etc.
It’s rather interesting.