Problem is that it has substantial side-effects with LONG-TERM use.
Yes, but in most cases you’re talking many years. Then some people develop eye trouble as the most common after effect of long-term use. But few are suggesting that everyone take this drug for years. They want to take it for a few weeks or months as a prophylactic, or have the option to take it for 5-7 days if they should test positive and/or show symptoms to keep the virus in check while the body builds an immune response (antibodies).