D&D was an odd game, for sure. I remember in one of our first sessions, one of my brothers rolled up a pair of halflings named Honest Bob and Friendly Bob (think used-car sales) who each had exactly 1 hit point. I don’t remember the names of his next characters, but he rolled them up about 15 minutes later, as the Bobs had been trundled off to Lemon Law Hell.

The most interesting difference between 3d6 and 4d6 IMO, is that 3D6 generates a normal distribution while 4D6, discard the lowest, creates a negatively skewed distribution which means the probability of any outcome leans towards better scores creating more “heroic” characters.

It’s important though to realize that the distribution and significance of modifiers associated with ability scores is quite different between 3rd edition & older versions of D&D. In 3rd (and later) edition, modifiers associated with high ability scores are much more important because they’re factored in to the CRs of encounters in a formulaic way. In earlier editions there’s almost no mathematical consideration of game balance (instead it was left up to DM’s discretion) and so high ability scores aren’t nearly as critical (though they certainly help!).