Compressors with high side crankcase

[NiHaoMike]

Why do some compressors (mostly rotaries) have the crankcase connected to the high side? It seems like it would increase the cost to make it withstand the high side pressure and creates the issue of refrigerant condensing into and diluting the oil on startup.

[RANGER1]

NiHaoMike, What type of rotary there are millions out there?

[NiHaoMike]

I'm referring to one of those:
http://www.tecumseh.com/en/united-states/Products/Rotary-Compressors/RGA5453BAA?fromsearch=1