You would use this to train your own CLIP/ALIGN model, most obviously, to give you image classifiers on steroids. DALL-E/M6 would also be trainable with this. (All at a smaller scale, but this is a good starting point.)
(For 47m maybe you're thinking of a cleaned subset from YFCC100M or something that one of them used, but they all use total images an order or two larger than Wit.)