Volatility is indeed the key to making money as a trader, not direction - as we are not investors, we aim to make money whether the trend is up or down.
But there are reasons to be more cautious shorting than going long -
falling markets often subject to low volumes and wild fluctuations against the prevailing downtrend, so always use a stop-loss:
a falling price can only fall to zero, so your maximum profits are finite, whereas your potential losses are infinite as there is not upper limit to a price:
falling share prices often attract a take-over bid, and this can sky-rocket the price overnight - unlike results announcements, such activity is not going to appear in any business calendar for the year:
in a general recession, the turnover of your service provider (stockbroker, spreabetting firm etc.) might fall to the extent that they are forced out of business - check the maximum compensation cover you will have on your account in case they go bust, and keep within the maximum cover.
Although TA in a downtrend is 90% (but not 100%) just the inverse of TA in an uptrend, the underlying markets are very different places. Don't expect the same results from a given trading system that looks great in an uptrend when the market flips over.