It's more than it opens the door for a load of projects. The 840av was planned for release with a bootable 7.1.2 in ROM, you could add this back in some day. You could also potentially do in computer ROM development with one of the new Quadra compatible ROMs.
Checking the date code, it is an Aug 1992, so not a release day machine, but interesting.
They're quite hard work - even recapping is fiddly. Take more care than usual. There is a lot of plastic near caps and hard to reach capacitors.
If you find a source of replacement DSPs, let me know before you order, I could probably do with one too. My dad's is battery bombed and it attacked the DSP a little.