What the CJP? Section 125 CrPC vs Section 20 BNSS

Yaar samajh nahi aaya! I'm having a tough time distinguishing between Section 125 CrPC and Section 20 BNSS. Both deal with 'maintenance' and 'support' but in different contexts. Section 125 CrPC is about providing living expenses to a wife/husband/children in case of separation/divorce, right? It's like the movie "Kuch Kuch Hota Hai" - you gotta take care of family, aapka liya hai. But BNSS (which is BSF Act, 2017) also talks about maintenance but for BSF personnel. I'm totally lost, please help! Why two separate laws for similar purposes? Please clarify, experts!