Interesting thought, I think it depends on the prevailing trend.

In a BTC bear market, I've found it good to hold fiat like you mention and focus on making gains in terms of fiat (i.e. trading USD pairs such as LTCUSD). That way you don't have to worry about the bitcoin price deflating your capital.

On the other hand, when bitcoin is in an uptrend, it's much easier to keep your capital in bitcoin and try to increase its BTC value by trading BTC pairs (e.g. NEOBTC).