I am complete naive in this subject area. What would you say to a clueless peer who said, "my laptop has those same features, except built into the CPU (like the AES instructions found in i7 cores) so they have less latency than a mainframe would"?

I cut my teeth on an Amiga and understand the appeal of external processors, but it seems like bringing those features on-die would be better yet. Mainframes seem to be going the other way, though. What am I missing out on?