I can’t help but wonder why they bothered with this crazy expedition in the first place

Lumon is a cult and the “real life” Lumon people probably believe that it’s a spiritual path.

Also did we just get conformation that they’re cloning people?

I think the current implications are that Lumon is cloning people but they’re not there, yet. I think Mark’s wife’s burned body was probably the clone and Miss Casey is the severed original.

The severance chip probably has the ability to do other stuff as well, like projecting the CGI “clones” into the employees’ brains and trigger that dream.