Snapshots are near-instantaneous, they take very, very little time to create and they only use space = amount of changes made during their existence.
As I mentioned, checkDB normally takes a snapshot of the database before it starts so that it can get a consistent view of the database without needing locks. So by creating one manually, you're just doing what checkDB woukld do automatically, no extra time, no extra storage space.
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability