If you avoid spending them for no reason and if you keep buying them,
I can guarantee to you that you will grow your coins

I would rather choose to grow my dollars....Bitcoin is not a good long-term investment for me...
Altough it is not a long term investment but some people still believe it the price will raise again so they stack a lot of bitcoin and wait that time to sell it all. But with growing dollars I dont think the price will raise high enough to get some good profit, may be its good but you wont get as much profit as bitcoin