The idea, it seems, is to avoid confusion. Previously, passengers with Group 1 on their tickets would be called after First Class, Business Class, etc., but that didn't stop some people from incorrectly thinking they were supposed to board the plane first, according to a report by The Philadelphia Inquirer.
"We are not changing the boarding order, just the group names," Ross Feinstein, a spokesman for American, told the paper. "Customers would line up and say, 'I'm going to be the first to board. I'm in Group 1,' not realizing that there were additional groups who were going to board prior to them. This is just more transparent."
It doesn't look like new boarding system favors more frequent fliers over economy passengers any more than the old system did. For example, if your airline-branded credit card guaranteed you Group 1 boarding, it looks like the same amount of people will get on the plane before you, even though it's now called Group 5, per the report. There is, however, an all-new final boarding group -- Group 9 -- designated specifically for people who choose American Airlines' new "Basic Economy" fares.