Here is why a cream keeps failing you.
A cream only treats the top. It never reaches the protected fungus below. On top of that, two things go wrong every time. First, you stop the moment it feels better. That is the exact moment the fungus starts to grow back. Second, a small dab of cream misses the spread. The fungus does not stay inside the red patch. It creeps into the skin around it, and the tube almost never covers all of it.
Top only. Stopped too soon. Missed spots. That is three ways to make sure it returns.
This soap fixes all three. You use it every day, so you never stop too soon. You wash the whole area, so nothing gets missed. That is how you stop the loop instead of just pausing it.