A single BTC transaction (on-chain) costs $5.56 in fees today. Minimum wage in El Salvador is around $300/month. How will people in-country afford this? Even the lightning network requires paying for periodic on-chain transactions.
They want to encourage investment. There are a lot of people who have millions of dollars of bitcoin and want to diversify into other assets.
I'm calculating 9 cents, not $5.56. Assuming 250 bytes (typical for 1 input 2 output transactions) at a fee rate of 1 sat/b (which have been regularly clearing lately):
Average tx fee paid != cost to commit a tx. A lot of people are intentionally overpaying to 100% guarantee placement in the very next block. You don't need to do this if quick settlement isn't an absolute requirement.
If one is living on $300/month why pay any transaction fee? Cash is free.
Predictably and timely transactions is critical for currency.