WHat is an EA?
You're so right. But most of the EA's (especially if it's paid) have backtests and trading statistics on neither real account or demo.Although I don’t trade with help of EAs, because trades cannot be fully controlled, I think that in some cases they can be useful, especially for traders with less experience. But I would recommend for EAs first to be tested on demo account before practical use on live account
I, for myself, use paid EA that I bought for about year ago. It shows itself pretty good. Not too high profits but stable and efficient