Hi,
I suppose do you mean the vmware.log (current) and all vmware-xxx.log (rotated, old ones) files located in each VM directory.
Well, the information in the files are related to the VM obviously, like VMotions performed, some information about VMtools, Reservations, etc.
So, it can be helpful if you want to know what happened with this VM, if there were any actions performed, I mean, is basically related to troubleshooting purposes.