It's about averages. The average NPC goliath is likely stronger than the average NPC halfling. The PCs don't have to follow those rules. So a STR 10 character, no matter their race, is just as strong as every other STR 10 character, no matter their race.
I mean, according to the game, that halfling needs 1 pound of food and one gallon of water per day to survive...same as that goliath...same as that medium-sized PC centaur. That's wild. And apparently horses, being large, only need 4 pounds of food and four gallons of water per day to live. That's uhm...wildly under what they actually need. Especially if they're doing any work. PCs in D&D, especially 5E, are the magically-enhanced superhero exceptions to whatever sense of realism we have.
The one that gets me is magically regenerating all damage after an 8-hour rest. That utterly breaks any sense of verisimilitude I have.
It's a fantasy game about throwing fireballs and riding dragons and battling giant insects and rescuing princes. So...shrug.