The question which is puzzled me is what useful information can be gotten from the cached time? Anyone can give me constructive viewpoint? Thanks in advance.
Only if you are curious to know how soon after you published the page, did Google visit and store it. Some people get excited about that. To me, it makes no difference. Smaller, low traffic sites can take weeks. Larger, more popular sites can take only minutes.
the info of cache page is not just important for you but also for your visitors.. coz' they might want to check what's on the past of your website..
It would be usefull if you've a blog and your host goes down, you can retrive your posts from chached pages