Grab Kalen's book, Adam Machanic's memory grants video and go over them.
Memory grants for sorts are, oddly enough, memory. If the process can't get enough memory, then the sort spills to TempDB. It would be decidedly pointless to request memory, get enough memory for the sort and still write to TempDB.
Oh, and spills are not the same as work tables, temp tables or table variables.
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)SQL In The Wild
: Discussions on DB performance with occasional diversions into recoverability
We walk in the dark places no others will enter
We stand on the bridge and no one may pass