Landing in close proximity to flak would make it more of a challenge to use, and make it more rewarding, but it's not "more realistic" to do that. Pilots generally wouldn't be manning the guns in any situation, so saying something is more or less realistic is sort of moot point in this regard.
Think of it as any regular res pawn that you do in the game. You landed, and you re-spawned instantly in a fresh plane. All this is doing is giving you another option on where to re-spawn.
Highly unrealistic.
But practical, and more importantly, fun.
One of my favorite things to do in Silent Hunter was load up a mission with airplanes all around and try to shoot them down with the 20mm AA before they sank the sub. In Il-2 that would be really interesting with the full-fledged DM and FM, or against human players.