Of course you could manage a better Ram/CPU ressources by disabling the screen display, yet this can't allows the use of the computer as a direct Musical instrument/mixing station.
Also the fact that *ZX spectrum 128 and +2 and +3 were all supplied with 128Ko Ram while CPC/Plus ranges still included 64ko Ram computers (464-664).
Despite being quite cheap, the 464 couldn't compete.
Also as most ChipTune bands also feature video projectionsfrom the used computer in Live-performance, the CPC would shine too thx to its somewhat better graphic ability.
==Godfathers of chiptunes on CPC==