The point is communication, usability, and reproduction.
Communication because "Pantone 123" is easier to convey throughout the chain than "C:11,Y:22,M:33,K:44".
Usability because Pantone swatches are easier to use in a design environment, and also easier to choose the swatch number in Adobe than to mess around choosing "C:11,Y:22,M:33,K:44". You can also give your client a Pantone swatch book and let them loose without them having to know about CMYK, substrates etc. etc.
Reproduction because you can ensure you consistently achieve the same output irrespective of substrate (uncoated,coated,glossy, paper, fabric yada yada yada ...). It also gives printers a well defined reference for ink mixing, quality checks etc.
TL;DR: It makes everyone's life easier, clients, designers, printers etc.