Just a thought experiment question: If an entity had one million bitcoin and didn't need it, they could chose to spend it, hold it, or give it away. What happens if they choose to hold it and eventually all bitcoin is owned by a few entities ? Would the rest of the world own derivatives of bitcoin and how would that affect the long term value proposition of bitcoin?

Also (beginner question) is it possible to transfer SATS via the lightening network to anyone, using a single app like Strike? For example, Can I send SATS from Strike to someone using a different App to receive it?