So because it is a potent immunosuppressive and anti-malarial medication it's also great for viral infections, right.
In vitro activity doesn't equate to in vivo activity, at best it only implies that, at least until there is evidence, solid evidence.
HCQ is used for the conditions you listed because there is evidence it works on them, because the benefits outweigh the risks.
Since we're in a situation like this, with no wiggle room for proper trials, we start trials like Solidarity and Discovery (do look them up before moaning). Some hospitals use HCQ, others get remdesevir, other still use Kaletra etc.
So imagine this, that French study is actually right, HCQ does jackshit. Then there is nothing to gain and more to lose. When you're propped to a ventilator, getting a Ducking ventricular arrhythmia really won't improve your survival odds.
You can freely access the COVID-19 topics on UpToDate.
You know, the best friend of any physician following the principles of evidence-based medicine and not some quackery.
Regardless, you do you, dude.