They allow a lot of latitude for mounting. Not every drill press is mounted
on a bench or the floor for starters. I've seen them attached to machines
being repaired, etc.
The other situation is clamping. There are times the table is turned aside
and the work is mounted on the base. The slots allow for using hold downs
on the work.
As Edwin said, it's for mounting fixtures, clamping parts, whatever you'd
use the slots on the table for, you can use the slots in the base.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.