Difference between Substitution and Supersession in S/4 and FIORI

[SteevesSegura]

Dear Gurus,

After reading many posts about Substitution and Supersession différences, i didn't understand.

Up to now I knew:
- Substitutions in ECC managed with Tcode VB12
- Interchangeability groups managed in APO with Tcode /INCMD/UI

I see that S/4 still refers to VB12 but added the concept of Supersessions in FIORI.

Please clarify the pros and cons for using one or the other.

Thank you.