Ooops, yes, I am referring to where this checkbox is in Version 2011.
As for the name, this style of report has been in use for 100 years before computers. The style of numbering and the format were pioneered by the New England Historical and Genealogy Society in the 1800's. They called it the "register report" and that is what most genealogists call this style of report.
There are some other "styles" that are used (in books not associated with NEHGS or other countries). Those are the ones listed at the front screen for those reports that FTM calls "Genealogy Reports". The dropdown box lists them as: Register, NGSQ, Modified Henry, and D'Obiville. I don't know where the other three would be used, but if someone needs a "Genealogy Report" in one of those formats, FTM allows the user to pick one of the others.
So, we have a semantics thing going on - the "register report" has been in use for so long and is so popular that any report like it (like the other three choices in FTM) are called "register reports" in normal parlance by many genealogists. Kind of like some people still call any "tissue" a Kleenex, or some people still call any "copy" a "xerox" - some people call this style report a "register report."
I can only guess that since "register report" is one of the four choices of format, and also because there are is no real formal rule for an ancestral report (that I am aware of), like there is for descendant reports, FTM decided to use the more ubiquitous name "Genealogy Report" for what most of the genealogical world would call a "Register Report". I personally would rather they called the group of reports "Register Reports" and then put "NEHGS" as one of the four options for descendant reports, but it's not a real big deal - most people will still be able to find where "register reports" are if they look at the samples.