I am asking this question because I accidentally found a trading system that was not working well for other currency pairs but it worked very well for CHF/JPY, see the P&L chart below.
It's used primarily as a hedge against carry baskets, as it's nearly swap-neutral. I wouldn't trust any system which doesn't test well against a variety of underlying.
It's lower-volatility than the other yen pairs, but will correlate well. It's useful as a +swap hedge due to its correlation and neutral carry.