Backtesting is very important for me. That was how I found some statistical edges/market behaviours which I use. Through backtesting you will also know if your 'ideas' have positive expectancy.
I already answered that question extensively. But if you don't read my postings you will keep repeating this question. For me trading is indeed easy now (for many years it was not). I am not interested in trading more often and I am not interested in billions. Read all my postings and you will know why. Quality of life prevails over quantity of money. But to understand that you should first make enough money to have the luxury that you can refuse extra money and receive in return quality of life.
Why not? Are you suggesting that it's impossible to be a profitable trader? Once you get to consistent profitability level it does become easy. First you a are consistent loser, then some get to brake even stage and some do eventually become profitable traders. One of my friends is into tech stocks, if he likes a company he opens a chart and buys on dips without margin, makes good money. Part fundamental, part technical.
Only newbies who haven't been around for very long say it's "easy". In 2007 everyone was running some sort of a dip-buyer and thought it was easy, then came 2008. He sounds just like those people (I used to be one of them), there will be a time when the whole tech sector drops -20% quickly and there won't be any bounce. I'm curious if you and your friend actually trade for a living, if not then it doesn't matter because it's more a form of gambling than a serious career.