I agree with him and it tallies with my experience, when I open positions, I look at liquidation price I'm going to get, and right balance is usually found between 2-4x leverage. I have positions open with leverage in-between same numbers since long time. I tried going above that once (10x with LINK recently) I sensed liquidation price was too close, but I went ahead with it anyway cause FOMO of bull market it didn't turn out well.
Just don't use leverage will give you best.
Bitmex Advanced Margin Trading Guide 2020. Margin enthusiasts will feel more scary after reading the guide. I don't share the guide to hook newbies to margin trading because it is always risky to use leverage, even just 2x leverage like Vitalik advised, just don't.
The guide can help newbies to know why their leveraged positions get liquidated by exchanges and know more about the risk, to avoid leverage.
Because they can understand the formula of liquidation, make calculation and think with 2x leverage, price will not crash to liquidation price but if price falls a bit, one round of liquidation will trigger another and more rounds of liquidations, then eventually price will hit to liquidation price of their open position which in their calculation should be safe. In reality it is not safe in market crash.
I'm of the opinion that margin trading is not bad, it is a good tool reap huge profits in short amount of time in bullish market, even if you are low on capital.