Concur is simply compliance software, so you are likely using some other software package.

If your profile through whatever corporate software you use has your SM number, that is in your DL profile and comes up as a choice. Presumably your employer has a corporate discount with DL and DL provides that to you (and reports back to your employer) when you book using your business profile.

It is a significant convenience to many people. If not to you, then it is just one more feature you won't use.