The comment made above about freeing up the fleet is a large part of my reasoning behind starting with an IC 2 tran buy, and typically another IC placed in FIC on j3 or J4, depending on declare round.
I will spend a tranny or two sweeping up the islands, but most of the time, I like to protect the trannies i am grabbing up the islands with.
My thought is this, a first turn IC on shangtung that cranks mechs all game, and a 3rd turn IC doing the same, is a 100 percent guarantee that India will fall quickly and efficiently, with no need for my boats to get involved, unless UK abandons its Egypt defense to reinforce India. Usually it is between UK5 and UK7 that UK pac is backing out of india and handing it over to me.
At the same time, my boats generally have no problem stacking up an island sea zone (mostly Java, for two-way options) preventing the allied fleets from suiciding trannies at my islands and preventing my bonus, or forcing me the spend my own to get it.
One of my nastier moves when things are going well in the pac is to stack up a NG SZ and put down a seabase, this creates all kinds of headaches, but it isnt always viable if USA is coming after u strong in the pac.
Net result is that I keep all the money islands, often also deny the Anzac NG objective, AND force India capitulation all at the same time. I dont believe this is possible without the commitment to ground and pound units from the 2 early ICs.
I also find that IC plus transports off the mainland are the best way to handle russia pushing its ground in on me.