FOR CMOS. it concerns about the speed which is about the edge of fall time. CMOS is cheaper and small area for IC chip.
For BiCOMS, it boostes the gain of the Op Amp,which is good for analog design. It all depends on project's requirement and your engineering judgement.
The main answer is money. CMOS transistors are almost free. And CMOS process in nano meter area is quite matured. So its very cheap to fabricate a pure CMOS chip, whereas BiCMOS cost money. So main focus is every function (either digital or analog) on CMOS. BiCMOS is used where there is extreme need of speed which is impossible to get from pure CMOS.
I hope this will help you see technology from industry point of view which is governed by money.
CMOS -- low power, low cost, less area, speed slower than BJT
BJT --- high power, high cost, more area, but faster speed than CMOS
so, when we need high speed with low power, and low cost. Then we go for BICMOS = cobination of both CMOS and BJT
CMOS is matured for a lot of high volume consumer applications. However, for specific cases (high speed com, very precise structures/references etc) you will need BiCMOS (SiGe, GaAs, and Si)