I see Bitcoin as a hedge against the USD and EUR as I feel the currencies will be in trouble in the coming years.
I see Bitcoin as a store of value. Keeping some of my assets in Bitcoin keeps some of my assets out of the hands of governments and banks and will not be affected by devaluation. There's no risk of a bail-in [0] for example.
I don't invest all my assets in Bitcoin, currently perhaps 10% of my net worth. I do feel Bitcoin will rise to 100.000 USD in the next few years and possibly even 1.000.000 USD in 10+ years, my aim is to gain a total of at least 3 BTC or so in the next year. I just hope Bitcoin doesn't rise too quick in value in that time period, since I can only afford to buy for maybe 1.000 USD per month.
I might sell a bit of my Bitcoin assets after my total Bitcoin asset value reach around 500.000 USD, since at that point I should be able to take things slow. At that point I would diversify a bit more into ETFs or stocks.
Perhaps this video [1] by Raoul Pal can give you some insight in my point of view, as I agree with him on most points.
---
[0]: https://www.forbes.com/sites/nathanlewis/2013/05/03/the-cypr...
[1]: https://www.youtube.com/watch?v=qL2LfVRl3J0