I don't see how ROI and the earning opportunities with Bitcoin have become relevant in this discussion when we are basically talking about Bitcoin becoming a unit of value.
Why?
There are two things: value that reflects on price, and ROI.
With higher value, Bitcoin becomes stronger and with good ROI based on past years, Bitcoin is possibly a more favorite investment asset. They are important to help to increase Bitcoin value, to expand its adoption and more. Without good ROI, or good speculative ROI, Bitcoin will no longer be an interesting and favorite investment asset.
Besides, Bitcoin has become an investment asset because people made it one due to its price being volatile since it has a fixed supply and increasing or decreasing demand makes it move up and down, but we all know that Bitcoin wasn't created to become what it has become today; it was created to be used as a payment method to make decentralized peer-to-peer transactions, but unfortunately, most people don't even know it can be used that way anymore.
Are you sure?
An asset that is used more with time, adopted more with time, will become more valuable, and it's just very basic. Especially Bitcoin is not inflationary like fiat currencies so its purchasing power must increase with time.
No fiat currency has a chart like this.
https://charts.bitbo.io/satoshi-per-dollar/