Agreed that rental property investment is usually terrible once you factor in all the time and expenses.
Yet I'm skeptical of Bitcoin demonetising houses in the near term. Most people I know buy the best house they can afford at the market price. It's not an active decision to "use it as a savings vehicle". Bulk of house price dynamics are surely driven by demand by residents (who will also pay rent, and hence help maintain revenue streams for landlords), and supply in a city (driven by building regulations and land availability etc.)?