Things never make sense when we don't understand them. Let me put some light into it trying to explain it better.
As we all know it, backtests are based on past events or historical data (that may have been tampered) and they don't reflect the truth, because things may not have happened the way they were registered. The same goes for forward tests on a demo account, they may work very well on demo (in some cases on a specific broker only) but when it comes to forward test on a real account things are different.
When we look at the top 10 strategies most of backtests are connected to a forward demo account and are taking the top 10 positions because they work very well on a demo account only, meanwhile the real accounts playing the same strategy with real money already been blown many times but the top 10 strategy list still lists them as the top 10.
With a backtest connected to a forward test on a Real/Live account things take a different approach because there's real money involved and they are being played on a real broker, at the same time the live account will reflect the strategy and will give more credibility to the backtest if things go the same way as they worked on the backtest.
A live account on a real terminal with real money running the backtested strategy will for sure make one more confident to make a decision when investing his money than if it's run on a demo account. Here the suggestion to separate them.
I hope I was clear enough, otherwise just ignore the suggestion or vote 'no'. It doesn't really matter to me, I know how to read the signs, and for the ones that don't know how to read the signs ...good luck! (you may need it).