They "sound" like big numbers, but to put some perspective on it, Bill Gates could come along and buy the annual ASE production 60 times over. The silver market is still very small.
ASE sales are considered to be an indication of what's going on in the physical investor silver market (as opposed to the paper market). Yes the sales are tiny in $ terms but used to extrapolate an understanding of the current physical silver market it can be useful. However like any sample, ASE's are just an indication and are by no means a valid random sample of the happenings in the physical market.