SQL Server - Benefits of splitting databases across different logical drives
is there any performance benefits to keep the data files split across different logical drives?

If all the volumes map to the same set of physical disks on the SAN there's normally no difference.
However, if each Volume maps to a different SAN LUN, it's possible for the SAN to allocate storage resources differently to the volumes.  For instance, they can be hosted across separate SAN controllers, have different caching policies, be separately monitored, etc, even if the LUNs share the same underlying storage.
If each volume maps to a separate set of physical disks, then splitting them up is very costly, as you can't pool and share IO resources between the volumes.  And as most database file IO is background IO, you should normally pool all the IO resources for all database files together to maximize efficiency, sharing, and per-database peak-IO throughput.
So, it depends, and you need to work with your SAN experts to choose, and to appropriately configure the SAN and the server (eg IO Queue Depth).