Why do you consider it a low point?? IMO, it's fairly important because it shows part of Vito's transition from lowly grocery boy, to someone who is feared and respected.
Had it been one of the sidekicks of Fanucci or somebody generally considered scary, then it would have been more effective. The landlord was a clown, before and after Fanucci murder. So scoring a point with him did not improve Vito's status in any way. But the reason it was low point and not just plain ineffective scene, was his character was more of a stereotypical "funny guy", you know, the Chaplinesque way.
