I save bitcoin now for both for fun and for future purpose. Because saving bitcoin is not a hard thing to do so I found it enjoyable and the bitcoin thatI got today and in the future will be saved and I will use it for the future purpose.
You are one of the people I found here who is not a hypocrite.

We need to admit that we put our efforts in earning bitcoin because we want to save it for future use. But what is that future purpose specifically, anyway? Well, it can be to sustain your daily needs, let you buy stuff you want, etc. So basically it is also intended for fun. Future fun, to be precise.
Mostly really wants to save it for future purposes rather than for fun that is if what implied is future for needs and fun for wants. Though we can't say that all of your bitcoins are spend solely for needs because a portion of your bitcoin surely been spent even just a little for your wants but there is no bad thing in doing that because it is your way to reward yourself as long as you have saved up.
Also I admire that the future purpose is definite that is the purpose is clear unlike others who says they do it for future purposes but has no real plan so in that way they tend to spend it in a non-meaningful way that ends in zero savings.
P.S. you can choose both as long as you manage your money very well.