> If everything in the economy is tied together, such that $10 is still an hour of work at a grocery store, and $10 still buys you a lunch or three gallons of milk, and $10 still buys you 4 gallons of gas, etc etc, then I don't see how you can say that there has been some kind of "secret" sky-high inflation over the past few years that is only detectable "from the outside."
The key ingredient missing from your calculation is time. If you are simply measuring how much an hour of work can purchase now, you are completely ignoring that some people want to save money.
If $10 is the measurement for an hour of work and 4 gallons of gas today, in a decade or so, you might need $20 to pay for 4 gallons of gas, and you might get paid $20 for an hour of work. But somebody who saved $10 worked today, and chooses to spend it a decade later, will only be able to acquire 2 gallons of gas. The result of their labour would have been reduced to half.
This is what Bitcoin intends to fix. We want to be able to store wealth into the future - so that an hour worked today is still worth an hour (or more) tomorrow. The potential appreciation in purchasing power is reward for thrift.
As it stands, if one wants to preserve wealth into the future, they must put money into risky investments to ensure that the dollar value of the savings appreciates at a greater rate than its purchasing power is lost to inflation. They also run the risk that their savings or pensions could be lost with companies going bust or if hyperinflation occurs.
Bitcoin is a pension plan.
As for using Bitcoin as a reference frame of measurement, there's a good reason to do this. Bitcoin is a fixed system of measurement which is disjoint of time or other externalities. There is an absolute maximum of 21M bitcoin, so any whole bitcoin is always 1/21M of the total supply. This is a truth that holds today and in a decade. It is immutable.
Consider measurement of length. If you only have cows in a field, how do you measure the length of a field? You could say it is 100 cows long and 80 cows wide, but how long is the cow? The cow grows as it ages. Once you get hold of an external tool of measurement - a meter (or yard, etc), then you can measure both the field and each cow against it.
The same is now true for economic value. Before Bitcoin, there was no fixed scale of measurement. The dollar was flexible, just as any other commodity. Bitcoin OTOH, is not flexible. The exchange rate of BTC/USD might be flexible, but when you use BTC as the frame of reference, you can instead measure how much value the dollar is losing against bitcoin. https://usdsat.com
As you can see, the dollar is losing value so rapidly that inflation of the dollar is negligible. It is the perception of inflation which is causing it to plummet far quicker than the actual rate of inflation.