Why the US Navy would reject captured German cruisers

What would happen if an additional German heavy cruiser joined Prinz Eugen in US Navy service after the war?

The US Navy would likely use both as test or target ships because their nonstandard high-pressure machinery imposed excessive maintenance and training costs.

The nominal combat value of the captured cruisers is judged insufficient to justify their engineering and logistics burden. German high-pressure machinery varied between ships and required specialist knowledge to operate and maintain. The discussion distinguishes theoretical understanding of the plant from the practical experience needed to keep it running. Those demands make disposal more attractive in this counterfactual transfer to the US Navy.