Well, as I see you don't have enough bravery to answer simple question about purpose of mini-computers, so I will.
When computers first appeared, they was big, just because technology limitations made small machines very expensive to use, so scale used to make computations cheaper.
In early 1970s, technology advanced to stage, where become possible to make simplified versions of big computers for some limited tasks, still too expensive for wide use.
Simple illustration, IBM-3033 mainframe with 16M RAM could serve 17500 3270 terminals, and PDP of same time could about few tens (may be 50, I don't know exactly), so mainframes even when was very expensive, but given good cost per workplace.
Known example, PDP used to control one of scientific nuclear reactor. PDP chosen, not because it have best mips/price ratio, but because it was cheapest adequate machine for this task, so is affordable for limited budget.
Very long time, mini machines stay in niche of limited machines, used to avoid much more expensive full-scale mainframes. They used to control industrial automation (CNC), chemical factories and other small things.
Once appeared microcomputers (CPU on one chip), they begin eat mini's space from bottom, when mainframes continue to become more cost effective (more terminals with appearance of cheap modems, etc) and eat mini's space from top.
And in 1990s, when appeared affordable 32-bit microprocessors and became affordable Megabytes of RAM, mini's disappear, because their place was captured by micro's.
To be honest, I just don't know anything we could not name microcomputer now, as even IBM Z mainframes are now have single-chip processor and largest supercomputers are practically clouds of SOCs (NUMA architecture).
And I must admit, I still see PDP's (or VAX's) on enterprises, where they still control old machines from 1990s (they are very reliable even when limited from modern view, but still work).
As I remember, last symmetrical multiprocessor supercomputer was Cray Y-MP, later machines become ccNUMA or just NUMA or even cloud.
From my opinion, NONE of microprocessors could be considered classic CISC.