I load directly from the tub, and wipe off any residual lather with tissue paper and put the lid back on.
I've never experienced any detrimental effect on the soaps (some of which I've had for 5 years or more)
What I will say is that scraping off a little soap to bowl lather is like using samples, and you don't always get the best from this method.
To 'air' or 'not to air' has been the subject of many a discussion on the forums.
Personally, I think airing the open soap for 24 hours after loading from it is for people who worry too much.
What ever works best for you is best.