Always listen to your wife!!!
Especially
TODAY!!!
As for MacKeeper, it appears to be a GUI for the basic behaviors in OS X. As you say, all the capabilities are already available in various other apps. Still, it may be more convenient to have them in a single place.
Not sure that's worth that rather unusual price.
I will say they have a very pretty (and usable) web site.
They appear to have throughly researched assistance in the US (legal as well as language). The one red flag I see is the "Anti-theft" capabilities. I'm not sure what info they are talking about that they will maintain and update once an hour.
I'm sure it's my prejudices affecting my fears...OTOH...
Perhaps reading some of the many reviews would be of help?
EDIT: The "anti-theft" function along with the "Geek on Demand" and the 3GB disk storage will be a yearly $39.95 charge. I can't justify that charge but it's optional, anyway. I guess it depends on how often your Mac is stolen, how often you call for support and how much (or little) you want to store in "the cloud."