CMYK images are only suitable for images destined for printing purposes. Your PC, laptop, tablet and phone screens – and our film recorders and photographic film – all use RGB. RGB has the widest colour gamut (the range and depth of colours in the visible spectrum) and CMYK is very much the poor relation, and just a means to an end.
Only have CMYK images? That’s OK, they can be converted to RGB. But for optimum quality, wherever possible, always work in RGB and supply images in RGB.