Art has monetary value because:
1 it is a famous, one-of-a-kind piece
2 it can be used for money laundering and/or illegal transactions
Pieces in museums are always in the #1 category. Any other piece with high monetary value is clearly in the #2 category.
This stolen van Gogh will probably end up in a private collection, but really, what's the point? Since it is now a known stolen piece it now has no value in both category #1 and #2.
I have a hard time believing that the new 'owner' had it stolen for the artistic value. Really, if he/she wanted to look at it, he/she could have just gone to the museum. (Well, not right now due to COVID19, but you get the point).