Long and short as part of a trading strategy you mean? Perhaps, although I haven't seen many long-term profitable grid trading strategies (not that I'm likely to see one published around the net of course!). Hedging used in a strategy you may be right, but as some sort of loss control or money management I would have to say forget it in my opinion.
hedging the same instrument is mathematically the same as just increasing/decreasing your positions in one account, as normal. And if you have to act on something to "hedge" then you can just as easily adjust your one account in the other direction. It is a belief and practice of newbies, not a hedging/trading strategy. Hedging is something like "Southwest obtains fuel contracts to lock in their price of fuel." Or "Investor X shorts the ES emini to hedge their portfolio of carefully selected stocks, to insure against catastrophic market collapse for a period of time." Or a car maker manufactures cars in several of their target markets, to protect (hedge) against catastrophic faliure of a currency in one of their markets (such as the Asian currency crisis 10 or so years ago, when currencies fell more than half)
With any trading strategy you are 'betting and waiting." If you are a trend trader your waiting for a exit signal, if you are scalping, your looking at the <5 minute exit timer. The only difference between trend traders, scalpers & GRID TRADERS (martingalers) are they don't have shit-loads of trades open to "buy time." They are trying to square positions as fast as possible. I am sure you can end up profitable with hedged trades, extra spread, extra roll at the benefit of protecting margin... betting on "regression to the mean"-- if you are comfortable with placing 10-20 trades to get same profit as 1 trade & you are comfortable with the opportunity/time cost. Be my guest. Fuel that fire!