I'm seeing some prefer not to buy boots.
the advantage of those who have boots to reach you is greater.
you'll have a harder time dodging it if you're not wearing boots.
some boots minimize incoming damage, or decrease cooldown, which is important, or even increase tenacity, when you get some crowd control.
For those who play as mage champions, magic penetration boots are extremely important!
buy the boots!
It doesn't have to be the first item, but don't miss the second item without having boots.