IMO, an arsenal ship with huge number of missiles is like putting large number of eggs in a basket. If the basket is dropped, all the eggs would be smashed. If your arsenal ship carried, say 100 missiles, is sunk, then your offensive/defensive strength is reduced by 100 missiles. And the cost to the enemy is probably just one or two missiles. That is a huge loss. And you are on the losing end in a war of attrition.
On the other hand, having large number of smaller arsenal ships, each carry 32 or 64 missiles, you can have a more versatile tactic to suit different battle environment, disperse or concentrate your arsenal ships, strength your chances of winning. Imagine having large number of enlarged "type 022", each carry 16 to 32 long range missiles capable of hitting 500km to 1,000km away, and move safely more than 100km at the rear or the flank of a battle group.
This trimaran is much smaller than type 056, judging from the 2nd photo at post #95. It is not designed to carry large number of missiles, especially long range anti-ship or land attack missiles.