Living Life on the Edge with macOS Sierra

With the introduction of macOS Sierra, I wondered if my wife's 24-inch Mid-2007 iMac with 4 GB RAM would have enough horsepower to support all the new features. She is currently using Mac OS X El Capitan version 10.11.6, and while the machine runs a little bit slowly, it supports all the basic functions that my wife demands of the machine: web browsing, photo management, and synchronizing with our iPhone and iPad mobile devices.

I found the macOS Sierra hardware requirements on this page. In summary, the following Mac models are supported:

• MacBook (Late 2009 or newer)
• MacBook Pro (Mid 2010 or newer)
• MacBook Air (Late 2010 or newer)
• Mac mini (Mid 2010 or newer)
• iMac (Late 2009 or newer)
• Mac Pro (Mid 2010 or newer)

Therefore, the 2007 iMac should not qualify for the upgrade. However, upon visiting the App Store, I was presented with the option to upgrade to macOS Sierra:

I am thinking of living life on the edge and see what will happen if I attempt to install the upgrade. What do you think--should I do it?

UPDATE: Since my original post on 9/24/2016, I had installed macOS 10.12 Sierra on a couple of other machines, and I found it to be similar in "bulkiness" and performance as compared with 10.11 El Capitan. Therefore, I decided to try upgrading to 10.12 Sierra on my old 24-inch Mid-2007 iMac. However, upon clicking "Download" from the App Store, I received the following message:

So I guess the system requirements are checked after being given the option to download. I am a proponent of not giving users the opportunity to make mistakes, but at least there was a safety net downstream of me deciding to install an operating system that was supposedly incompatible with my machine.