Service accounts adding to Local admin group

Hello Everyone,

What are the risks with adding SharePoint service application service accounts to local admin group.

I see in many Microsoft blogs not to use farm account to create service application and better to use dedicated service account but i didn't see any articles why we shouldn't add dedicated service accounts to local admin group

I am facing some GPO issue and one my friend suggested to add service accounts to add local administrator group to fix this issue but i am not sure what the risks behind it. 

Please let me know if you aware of risks.

Thanks S