A lot of games operate at a high enough level where abstraction does a decent enough job. All of the units in Empire of the Sun, a game about the war in the Pacific are face up and available at any time to see, but you don’t know if the opponent is holding a response card, or, will be able to respond to your operation. As a strategic game, whether the enemy understands your intentions is important, and it’s honestly one of the few that has some kind of intelligence factoring baked in.
At the levels I think you’d be more familiar with, though, it’s a real challenge to make intelligence work right because it adds an enormous amount of extra admin to hide units, especially when you play on cardboard and not VASSAL with a handy mask function. It may sometimes be worth it, but you never know.
ISR in general is one of the more technical aspects of war that, a lot like logistics, and in earlier eras, siegecraft is very hard to get in there without a lot of bandwidth being taken up. Games can feature siege, but we don’t have a lot of great mechanics for the technical aspects of rationing, mining, construction, etc that really determine the skill in siegecraft, so current siege games tend to be more ‘assault’ games.