The standard argument from mainstream academic microeconomics why money should be inflationary is precisely that this causes existing contracts to automatically get repriced in real terms, and that this helps avoid the real impact of financial shocks on the economy, see Nominal rigidity - Wikipedia or Paradox of thrift - Wikipedia
In practical terms, it’s just a coordination measure. If your central bank is boring, predictable, not compromised, and gives a regular, accurate report that tells you that “x BTC” is enough to feed a family of four for a week on average in your country, you might as well say “x BTC = $200”, and set your hourly consulting rate in dollar terms. Then you can spend your time actually working, not having to worry about halving your rates when BTC goes from $20k to $40k.
Just denominating in BTC is certainly another option; whether it’s simpler depends a lot on how stable the real value of BTC is.
The advantage of the approach is that it’s opt-in: if you think dollars are simpler, you use them; if you think BTC is simpler, use that; if you want to do one-off transactions with someone who thinks differently, it’s trivial. Of course if you want to commit to a long term contract with someone who thinks differently, you might have to do financing, which is no longer trivial, but also no worse than long-term international contracts today. And unlike today, in this model your actual savings aren’t being put at risk by bad central bank policies.