Why do we have this? I don't understand why 16 isn't allowed on some races while doing the point buy. For instance if I want to eventually make a tiefling paladin, it will suck if I can't have more than a 15 strength to start.
It's part of the official ruleset the game is based on. Different races get different bonuses to ability scores. And you can't assign more than 15 to an ability score before racial bonuses when creating a character.
In regards to tieflings, however, you can get 16 strength by choosing the subrace Zariel tiefling.
