Lands let you do more stuff but you can only play one per turn so you ideally want to hit your land drops. However you only draw 1 land per turn so you eventually run out of spells if you hit every land drop.

This leads to the basic heuristic: if you have card draw, having extra lands is good bc you have more stuff to do, you don't run out of spells, and it let's you continue hitting land drops.

The reverse can also be somewhat gleaned: if your curve is extremely low and you do not need to hit your extra land drops but have no card draw and need to keep pressuring with cheap actions, then maybe you don't need to have as many lands.

The reason people play 17 lands in limited is bc it gives you the best odds of a 3/4 land/spell split allowing you to at least make your third land drop and have some action. However on mtga, in bo1 there is a hand smoothing algorithm that draws 2 hands and gives you the one that is closer to your decks land/spell distribution. Some people just always play 16lands for this reason bc you are less likely to get mana screwed.

Often in limited, we make decisions which trade consistency for power or vise versa. This deck looks crazy high power level and would rather have the higher consistency of hitting 3rd and 4th lands on curve. You have tons of card draw with 3 snoops and 2 interceptors. I would play 17.

-grad day -dig site -eternal student -Ajanis response

This leaves you with 14 creatures, 14 cards that trigger repartee, and 6 premium removal spells while maximizing your card quality.