iBGP multipathing through route reflectors - is there any reason not to use the additional paths feature?

For those of you who don't know, the BGP additional paths feature allows RRs to send additional paths on top of the one that they select as "best". If you have a higher ibgp maximum path value set on your routers, they can actually install these additional paths in their routing table. I'd like to know if there is any reason why this shouldn't be enabled, and if it is common in service provider environments.