Well these Type 022 can carry 8 C-802/803 AShMs in its arsenal, same number which the F-22Ps can carry, thus they have the same firepower with respect to F-22Ps when it comes to anti ship missiles and same chance of hitting the target.
With good anti-missile defence system on ships, I only see a good chance of hitting the enemy ships with a mass attack strategy, meaning 3-4 missiles coming at the same time towards the target, thus giving good chance that 1 or 2 may skip the anti missile defences of the ship and hit its target, single missile would have very low chance of hitting its target as it can be easily taken down.
So the C-802/803 type of missiles should have good speed, possibly around Mach 2 or more in its final phase of attack, low terrain capability, less RCS and 3-4 or more missiles attacking a single target at the same time, then good chance of damaging or sinking the target. Here these smaller FAC boats can be useful, they can launch a heavy fire of multiple missiles, can have platforms to be loaded out at sea or can be easily loaded at shore bases and then head back and the loss of such a small FAC would not dealt a big blow to our defensive force, thus due to its usefulness, cost we can employ more of them and cover more area and harass the enemy much more compared to larger frigates, which would be easy targets and if sunk or damaged, can be a moral buster.
15-20 of these smaller FACs are a very good force and used as offensive weapons, data linked with frigates or AEW&C / fighter platforms.
And these C-802/803s can be pretty deadly missiles, if not sunk its target, can surely damage it enough to be taken out of the war.