Whats the deal with the "Forgotten Realms Races"

https://preview.redd.it/q82t2lni103h1.png?width=791&format=png&auto=webp&s=e07cfa2286fca682227e8d2a7961bafcd2c64b81

Can someone explain to me why these races exist, and how theyre different? Is it even important enough to mention to my players?