Timing doesn't matter for the Intent.  GSA, for example, will only add an icon after the user returns to the home screen.

I don't mean in terms of the animation, only that sometimes the icon seems to take a few seconds before appearing on the home screen so in demos I always wait a couple seconds in Chrome before tapping the home screen button just to be sure...

Fwiw I don't know if this feature is currently used often enough to warrant optimization for first-use only. In any case, it's easy for the user to go back to where they where, but it can be hard to later remember how an icon ended up in your home screen (I've personally experienced that a few times).

Not something for which I'll strongly argue, but seemed worth bringing up.

I'm kinda unsure about whether this is a good thing...

On the one hand, doing this every time you added something might get annoying as we're breaking people's flow. On the other hand, things that work first time only can be confusing for users (i.e. it isn't consistent / repeatable).

Replacing myself with chowse, the primary Web Platform design contact

This bug is over a year old and this topic has recently come up in other areas, so just archiving. Please reopen if you want!