Except the most usable crypto today which is Bitcoin, might cost 15$ to send someone 5$ today, maybe 20$ tomorrow depending on the ever flactuating gas fees. I wouldn't describe this as low transaction fees nor in any way efficient. Crypto right now is at best an inflationary tool good only for profiting off market speculation. It will never be as good as fiat or any other financial products based on fiat for the foreseeable future.