Keneton, I'm comfortable playing with or without. Each offers its own benefits.
If I'm playing on a drawn on map, with miniatures, I know exactly what's there, and might be inspired by it to do something cool that I might not have otherwise thought of. "Hey, there's a coffeepot in the office! I grab it and throw hot coffee into his face!"
I as a player also know (or can quickly determine) exactly how far away something or someone is. My character usually will not know to that level of precision, and trying to run up and punch a guy might take one Phase or two, the character won't necessarily know. "I rush the guy, and tackle him! Uh oh, he's leveling his gun at me, and I'm still ten feet away..."
If I'm playing without a map, then I'm not limited by the environment. "Before he can fire, I quickly fling open the closet door next to me, and use it for cover!" GM: "Sure, there's a handy door there. Give me a DEX roll."
I won't know exactly how far away someone or something is, which adds an element of guesswork and danger to declared actions. "He's around 30 feet from you," "The forklift forks are about 4 feet long," "She can't possibly make it to the self-destruct button before you can stop her... or can she?" On the plus side, it's a little more thrilling, but on the downside, it can be easy for the GM to forget or fudge the results.
So, by not using a map and miniatures, the players aren't necessarily "giving something up," they're just playing differently.