I'm not you, so I don't know what kind of use your MBP is getting. But, if 8GB is doing well, there is no point in upgrading. An 8GB stick of 1333MHz laptop RAM is well over $500 (from what I know, at least). If you do need the upgrade, but it's not urgent, then wait a while. 2x4GB is around $80. My guess is that it won't be too long before 8GB sticks are much more reasonably priced.
16gb would come in handy for heavy users of adobe creative suit, 3d software, VMs, etc. Cost/benefit ratio in a laptop is iffy at this point, but it will become commonplace. To think otherwise is to ignore the historical precedent of 30 years of computer progress.
16 GB memory is compatible with the MacBook Pro 2011 and newer.
It's just that... it's extremely hard to find 2x 8GB and even if you do, it'll cost $1000. (Cause it's extremely difficult to put that much ram into that small chip for a laptop)
And that ram you just showed us was a desktop ram, not a laptop ram.
Besides, why would you want 16GB ram? It's not going to make it run faster unless you're running 1000+ tabs, running and rendering a HD video 1080p, photoshop, etc.