Operations Manager has many features that were introduced for the R2 release that are not available in the Operations Manager SP1 release. One of these is the PowerShellmodule, which greatly increases the performance of PowerShell scripts in MPs. The best practice is that MPs that are intended to work on Operations Manager SP1 should not use this R2-specific PowerShell module.
The majority of Operations Manager customers are still on SP1 due to how the products are licensed to customers. If an MP is intended to work for the maximum number of customers, it should work for SP1 and R2 customers, and all MPs designed for SP1 will do so. Developing an R2 MP that does not work at all for a customer on SP1 could alienate a large number of customers.