"It’s Like A Huge Miniature Golf Course"

[Psychosplodge]

And the Lord spake, saying, "First shalt thou take out the Holy Pin. Then shalt thou count to three, no more, no less. Three shall be the number thou shalt count, and the number of the counting shall be three. Four shalt thou not count, neither count thou two, excepting that thou then proceed to three. Five is right out. Once the number three, being the third number, be reached, then lobbest thou thy Holy Hand Grenade of Antioch towards thy foe, who, being naughty in My sight, shall snuff it.

[Charon]

I think nobody would argue that abstraction is a problem when it allows you to immerse yourself in the battle.
Grenades are a bad example because it does not break this immersion. There can always be a reason why it is only one grenade (besides you are not in that range very often anyways).
Rules/abstractions that completely contradict the background do break that immersion.