Your right its a push.
But it has other benifits ,not used in boxing.
If used on to a finger tip strike with a loaded wrist it can penetrate the softer areas.
With gloves it is just about usless unless you want to blast your opponent off of you in a clinch etc.
Even so to do that would be better if you could blast him off with one high palm strike and one low both going out at 45% over one of his arms with that step through onto the end of it.(not leagle in boxing though).
Those are the techniques from Wing Chun that mr Lee added onto to create the one inch punch.
Getting snap onto the end of the thrust is difficult.
Although if you have completed iron palm training and practice bare handed chi sao you can accidently split face skin with it.