The reason for Bitcoin's success is that it is a great savings vehicle. It has so little competition in that regard that every other use case is a rounding error. I know people don't like hearing that...
Savings dominates because Bitcoin solved the hardest problem: preserving purchasing power across time without trusted third parties. Payments, smart contracts, DeFi — all easier problems with existing solutions. Store of value has no substitute. What happens to the ecosystem when the holder base shifts from speculators to long-term savers?