The entire BTC market cap is minuscule -- about 600bn as of this writing.

That seems like a lot, but compare it to Apple -- the market cap of just this one company's stock is currently ~2,238bn.

The market cap of gold, US dollars, Euros, etc. are all many times more than Apple. The value of all BTC is a tiny microscopic speck compared to the amount of USD or gold in the world.

This means (among other things) a few small players (with tiny capital relative to, say, the size of all USD) can swing the BTC market either way with a comparatively tiny amount of value moving around.

That would seem to greatly limit BTC's usefulness as any kind of inflation gauge for the broader economy.