Rain can punish cage really hard with 40% AA's and 40% RH started combos, 44% 4 RH Combos, and 50% JIP Combos, all of them take one bar and drains the opponents bar.
He has the ultimate anti rushdown armour, and when rain players dash cancel instead of letting the RH go, it becomes a serious threat, cafe is forced to crossover and or pause his rushdown in respect.
A F0xy Grampa can shed more on this, he mains both.
Rain can be out zoned by IAF characters, and out manovered by high mobility.