Whats the freaking point of working in AdobeRGB or ProPhotoRGB if I plan to export it in sRGB ?

I just watched thousand of color managment videos where people recommend to work in wider workspace than the final output.

As I heard the number of an image colors always stays the same no matter which color space I am using. So if I plan to export in sRGB how can I work with the colors that are outside sRGB?

If r:0 g:0 b:255 in sRGB appears as different blue than r:0 g:0 b:255 in AdobeRGB, what is the point ? How can I edit with the color from AdobeRGB that wont be shown/ won't be the same in sRGB ? showbox

It might be basic thing for some of you but im stuck at this point and cant get over understanding this.. Color managment is the most frustrating topic I ever tried to learn.  usps tracking