Direct EV calculations are the first step in figuring out how to calculate "maximized EV" based on situational considerations. To become a better player, you will very much care about the size of your positive EV.
Sure, the basic EV calculations say to either bet, call or fold based on card odds vs pot odds. Usually, you're only really looking for a positive or a negative EV. However, when you start playing against better players, you need to work on maximizing your EV to get the most value of a particular situation. This gets into implied odds and equity.
Here is a link to a good article on the subject:
Cards Chat: Expected Value & Poker Explained
In certain situations, your expected value may change or be maximized if you check-raise, or you lead out on the flop with second pair or just air (making your crappy hand look better than it is, thus altering your opponents calculation), or calling a bet on the flop where you can make it look like you hit a straight or flush on a later street, or betting on the come for a flush or straight. However, where these are advanced plays, to get the correct EV, you need to put your opponent on a hand AND guess what they will do in a particular situation. A classic EV maximizer is the slow-play of the flopped set when you know you have an aggressive player to your left. Simple EV would have you bet out rather than slow play.
You might notice that some of these situations would potentially give you a positive EV even though your cards have you drawing dead. Then your playing real poker, my friend. Just don't do this with idiots or beginners, as the great Doyle Brunson sagely put in Super System I: "you can't bluff an idiot."
Just pulling these poker plays is not interesting unless they are done in the context of a situation and possible outcomes based on a psychological profile of your opponent. Then you can get the the next level of EV. The math is a little obtuse and I can't imagine someone really doing the EV math for situational poker on the fly in their heads, but you could understand the EV impact of various plays, such as the tried-and-true check-raise, and apply it in the correct situation to get a boost in your overall EV.
Also, "maximized EV" plays go both ways with poker players. This is what the top players mean when they talk about the "mental warfare" that goes on in big tournaments and big cash games. While you are working our your EV maximization strategy, your opponents, if they are good, are working out theirs. You have to incorporate what you think they are thinking and what they think your are thinking into your EV calculations. Some guys are just natually good at this. That is poker talent, IMHO.
The idea behind poker, especially tournament poker, is to maximize your win when the opportunity presents itself. Simple EV can "leave money on the table" so to speak. If you can maximize your EV you'll, over time, simply win more money/chip is a shorter period of time. And money/chips over time is how we keep score in poker.