I dont belive it makes any diference, i Never used win bonus, and i have a few trophies, not so many, but with a 35T budget i dont think it is to bad.
At least at lower levels, from 1 to 4, it dosent make sense, i manage to promote my 3* team without any problem on that levels.

It is just like moral, i have a team were i dont give moral boosters to the players, and they continue to score and win, the only diference is the number of cards, it seems they get more cards.

But like many things in this game, all of this is based on the individual experience of every player, so unless Nordeus could tell what it is really True, nobody can know for sure.