As a bioweapon, this one is pretty shitty. Bioweapons are typically used like nerve gas; area of denial weapons. Anthrax is an ideal bioweapon because it produces spores that are relatively stationary, but carried back by troops and shit. The problem with area of denial weapons is that they're indiscriminate and basically useless. Nerve gas and chemical weapons can blow back on your own troops and bio weapons can have unintended targets.
Not to mention if you make a bioweapon and it spreads all over the world killing millions and people find out its you, your nation is pretty much gone. Bioweapons aren't and never have been worth it unless you're a doomsday cultist or a terrorist.
Its like a nuke you can't control, its functionally worthless. Not to mention they're expensive, difficult to make and prone to shit like this. Which is why China would develop one, they're fucking idiots.
There's three types of bioweapons.
You have your MAD versions, which are lethal as fuck and fast spreading and linger around in the animal kingdom and in feces/urine. Shit like enhanced smallpox, y.pestis modded out, and other shit. It's designed to have high infection rate, quick acting to the incapacitation stage, nasty 7 or higher spread ratings, and can be carried by livestock and rats and pigeons. End of the world shit ala Captain Tripps (Which burned too fast).
You have your debilitating agents. These are designed to linger around, low lethality but incapacitating symptoms, designed to keep troops in the barracks or at the medical stations, the hospitals overburdened, the factories unmanned, and the population tired and sick. Anthrax is in there, but not too good because its lethality is up there. Weakened smallpox is good, modded influenza is good, one of the pneumonia variants are OK.
You have your chronic ones. Corona-virus fits nicely in your little arsenal there. Long incubation, high spread value, debilitating with a taste for the old and infirm (That's party leaders and career politicians and older generals right there, as well as the rich and powerful, meaning everyone will see THEM getting extreme life saving measures while Joe Chink has to die in the gutter), moves through the animal population which can effect livestock and wild animals.
It's actually pretty goddamn close to a bioweapon developers wet dream. Maybe try to tweak it so it's communicable while it's still in the invisible incubation stage, but that runs the risk of not being able to detect it before it's infectious meaning it can run out of control.
Now, you combine it with swine flu FUCKING their pork production, rumors this came from wild eating, and all the other fun stuff, combined with a hilariously inept totalitarian government, and you've got a match made in heaven.
EDIT
Kill everyone bioweapons are part of the MAD system. Good for wiping out the world, bad for warfare.
You want to take over the country, as well as its people. Rolling your troops into where there's nothing but corpses and end-stage hysteria spasm damage might seem great, but all you've got is a large area that quickly moves to anarchy and worse as everyone rushes for the newly opened for colonization land.
You wanna keep troops in the barracks and unable to fight, the factories offline, the infrastructure overburdened and paralyzed, the food delivery systems shattered, the politicians sick, the generals sick, and the civilian population unable to fight back as you roll in and begin immunizations of the populace and delivering food and getting their water, sewage, and electricity back under your benevolent rulership.
Not roll into a massive cemetary full of fucking corpses that have now given you a SHITLOAD of other problems since you have 1.2 billion people rotting in the streets, buildings, subways, and everything else, with damage done in the hysteria phase having caused massive disasters.