3 strikers are important for me even though I never play with all 3 in one match but first they are useful when I like to rest one of my striker for an important game in CL or CUP

Second if they are multi positioned like AMC and ST this gives you options in the game to play with different tactics

if you talking about GOAAAAAAAAAAALS you should have an eye on assists too if he doesn't score? some strikers dont help in scoring but opening spaces in opponents defense