Suppose you earned 60
BTC by working hard for 5 years and one day you decide now you don't want to work then what would you do with that amount?
How would you invest that amount? What will you do? Hold it dreaming the price will rise? Sell it and invest the fiat? or start a business? or retire? Any ideas?
Just ask directly, what would you do with half a billion usd dollar?
It hugely depends on where you live. There are a lot of possibilities to spend that money in a wise way. For example in some countries you can buy up to 7 amazing apartment up to 100m square and then rent them while in USA, Great Britain and similar countries you are very limited to do that action because apartments there are very expensive.
You can also start official bitcoin exchange service with partners and etc if you live in small country. You can buy bitcoin ATMs and set them in your country. You can buy miners and mine bitcoin or altcoins. You can also make datacenter and start hosting business by letting others to host their servers in your datacenter.
See how many ideas can be just written so quickly. Think well, business depends on your country because demand on things, products and services is very different from not only to country to country but also from city to city.