As long as there is fiat money, people will always first spend it since it is inflationary, so the scenario that bitcoin used for daily spending at large scale will never realize

Then the major usage left are long term saving and international remittance, both happens at very large size (over $100) and very low frequency (once a week/month)

In fact, majority of the transactions today in bitcoin network are pools paying miners and speculators deposit/withdraw from exchanges/gambling sites.

Gambling sites could occupy large amount of transaction capacity of the blockchain, how to move their large amount of traffic offline is a challenge, maybe they should cooperate with bitcoin exchanges and do internal settlement without direct receiving coins from individual users