“Sideways” means low volatility; the extreme of sideways-ness is price stability.

The theoretically ideal form of money is price-stable.  Volatility only benefits traders, at the expense of everyone else.

If BTC could become price-stable,^* then I would prefer that.  The world cannot run on volatile money alone, nor on deflationary money alone.  (Note to Jay:  I am perfectly well aware that price-stable BTC will never happen.)

Since I don’t swing-trade, the only thing uncomfortable to me about a sideways market is that I never know whether it’s about to crash, or about to moon.

---

^* I mean price-stable according to an index of goods and services.  That means rising against the dollar, as the dollar depreciates from inflation.  The dollar is not price-stable; to the contrary, the dollar is a volatile currency.  Have you seen dollar prices lately!?  Not only the obvious increase in prices, but the fluctuations as markets adapt to price shocks.