I think Bitcoin is something that the world wants and it gains power, it doesn't lose it. There will come a time when we can use Bitcoin everywhere. On the other hand, I think it could happen that if you buy something, you have to pay Bitcoin instead of money.
If, in the future, you mostly use bitcoin for payment means that you need to earn in bitcoin, otherwise your bitcoin stash would diminish.
With bitcoin being deflationary, it is not an easy task.
Personally, i would prefer to simply loan some btc to a "bitcoinbank" providing that it will give me the yield in bitcoin.
Currently, when you take a loan against your btc, THEY ask for 10-12% yearly (in cash), which is outrageous.
I have seen the numbers of 4-8% interest in bitcoin for your bitcoin.
Blockstream was talking about it, but I am not sure whether it was finalized or not.
Realistically, it would probably be around 4% and not 8%, but we shall see.
Additionally, if you can go in and out with ETFs (creation/redemption), it would nice too .