Earlier quoted context omitted.
It's analogous to investing money in USD or GBP before those countries were given a license to print as many USD and GBP as they wanted. Before then (1931 for the pound and 1933 for the dollar, though they maintained de-facto parity with gold until 1971), dollars and pounds were considered good investments. That's why we had bank runs: people thought their money would be safer under their mattress, and preferred to o…
A deflationary asset class encourages hording, not spending or using in other ways. There's also no real limit to the number of crytocurrencies that might appear later (see: MySpace replaced by Facebook), unlike gold. As for inflation: safe government bonds have historically kept up with that over the long haul, so no big loss there.
Back in the day people used to get interest (covering more than inflation) from holding money in their bank accounts. What's changed?