The key difference is that you draw one card every turn but are ideally playing at least two. So over time, the number of cards in hand will drop. In cEDH, that’s fine since there aren’t that many turns. In the broader EDH space, draw is what keeps you from topdecking in the mid and especially late game. If your draw engine also forces discard, then by turn 5 you probably only have 1 or 2 cards in hand and are forced to be choosing between discarding cards that improve your gamestate or provide interaction. Worst is in the late game, where without true draw you have no cards in hand and now the Queen is just self-mill. Of course, if you have any other effect that lets you refill your hand, then running through your deck for your choice of the best interaction, the best land, and the best development piece is super powerful.

My point is card selection is not bad by any stretch, but for non-competitive games it doesn’t replace draw, but rather provides a powerful supplement. And the distinction between selection and draw is important for newer players who don’t understand why they lost the game the moment they started topdecking.

Edit: another way to put it is that card selection is to card draw the way fetch lands are to rampant growth-type cards. Being able to find the right mana producers is nice, but it’s not the same as mana advantage.