No, you can't really know the condition of said instrument just from looking at a picture. But you can pick up on major and even minor defects and some damage. Of course there is risk reward, sometimes you may never find another one again.
The thing about auctions is that you can pick up, a clarinet in this case, for a third or less than what retail would be. If you want to have someone repad it etc that is extra cost. But of course if you want to repair yourself, the cost is relatively minor, just an investment of time. Naturally there is a small investment in basic tools to do the job.
The other side to an auction is money and rarity. There are some instruments that either you just won't find in retail or even specialty that you may desire. Generally something that is 100+ years old isn't carried at guitar center. As with anything this is a bit more niche. You can repair and resale of course, that is the money side. How many students need band equipment? Most will never be serious players so a plastic Yamaha, Vito, Jupiter, artley etc will more than suit them. Buffet, selmer and the like make some good sticks but everything doesn't revolve around them. People want what they want, some people are willing to put out good money for something like a 444 or say a boosey 1010. There is nothing wrong with something old if it still does what it was intended to do.
* of course I just do it for fun.
