Why steal a Henry Moore?

Thieves simply drove up and loaded a two-ton Henry Moore statue into a truck.  But why?  Some commentators fear the statue — worth millions if sold properly — will be melted down to scrap and sold, possibly for no more than $9000.  It is hard to sell famous stolen artworks, and the number of clandestine buyers is smaller than many people think. The Financial Times (22 December, p.6) suggests another hypothesis:

…stolen masterpieces have other uses.  Criminal gangs sometimes use them as surety in deals: a drug dealer might give a supplier a 3 million pound painting in return for a batch of cocaine.  When he has sold on the cocaine, he pays back the supplier and the supplier returns the painting.

Is the use value of paintings so high for thieves?  It is odd to value collateral by its cost of production (i.e., its theft), or its non-realizable "white market" value, but nonetheless this sounds like a coherent equilibrium.  If you can steal a multi-million two-ton statue, and prove it, obviously you are a man to be trusted.