Arbitrage = +EV, right?
The way the +EV is "created" through arbitrage is because at least one side is +EV. The 'other' side might be -EV, +EV, or 0 EV. Regardless, a +EV side still exists and you don't need to bet the other side to be +EV.
The concept of +EV isn't some newfound knowledge or anything weird. It's very straightforward at its core -- if the probability of winning is greater than the (implied?) odds on the wager, then it's +EV. This is the basis of advantage play. Although sports betting is a different animal than other forms of AP, the core to winning is the same: Make +EV bets.
Not to mention, you can't be a "winning" sports bettor without being a +EV sports bettor. By "winning" I mean long-term expected to make money/profit (and not the "has won due to luck" type).