They had experienced Easter Day, and then gone back to business as usual, not unlike many a twentieth century Christian. For Saul, the vision is anything but conversion. So far it is simply recognition. He stumbles along the road, blinded by the light, still not comprehending what all of this will mean for him. Here we have one of the most dramatic and well known visions of the Risen Lord in the history of Christianity, and it hasn't done a thing but leave him blind and confused.
Visions can be like that.
He too had a beatific vision. He wrote down an account of it and quickly sewed it into the lining of his coat. Because he knew that the intellectual side of his existence would very soon cause him to begin to question its authenticity, let alone its meaning for him. He wanted to be able to touch the account, sowed into the lining of his coat, to know he was not mad, nor had simply made it up. Visions are not enough.