Arrays of operation give us a a lot of benefits, especially when you use them in assemblies. For ex. patterns of 100 holes in part can be used in assembly to insert 100 shafts in two operations.
1) Insert shaft in one hole
2) Pattern that shaft to the holes, by selecting hole pattern from the part.
 
All that benefits are lost when you use a part exported from multi-body part. In such an exported part you can't select patterns used in multi-body part.
 
Instead of inserting parts separately with separately constrains, from my experience, when you insert parts with pattern, Inventor works much mor faster with large assemblies.
Also such a technique improves work a lot and helps to save a lot of time
 
It would be very useful if Inventor could export pattern information to part from multi-body part.