During this year’s E3 press conference Phil Spencer dropped a bombshell with the announcement of backwards compatibility on Xbox One. This feature will allow gamers to play Xbox 360 games on the Xbox One and even utilize functions of the newer system such as screenshots and Twitch broadcasting. After the announcement gamers took to the internet and debated the merits of backwards compatibility and whether or not this would help the Xbox One.

Last week I had noted a comment from Microsoft’s senior marketing director that Xbox One sales increased by 79% over the previous week during E3 and speculated that backwards compatibility must be at least partly responsible for the boost in sales. The head of the Xbox division seems to agree.

Phil Spencer took to Twitter yesterday and responded to a user asking if the sales increase was due to the backwards compatibility announcement. Spencer wrote that he believes backwards compatibility matters and pointed out that there are a lot of Xbox 360 owners who had not yet made the jump.

While the evidence is circumstantial, a strong argument can be made that the announcement of backwards compatibility did indeed help move Xbox One systems from store shelves to gamers’ entertainment centers. At the end of the day having potentially hundreds more games playable on your system is a positive feature.

A number of notable game publishers like this feature as well. Ubisoft has praised backwards compatibility and will be including Rainbow Six: Vegas and Rainbow Six: Vegas 2 with the Xbox One version of Rainbow Six Siege. Originally released for the Xbox 360, the Rainbow Six: Vegas games will be fully playable on Xbox One thanks to backwards compatibility. Bethesda SoftWorks has also jumped into the pool and is offering a free copy of Fallout 3 with pre-orders of the upcoming Fallout 4.

Backwards compatibility is already available for Xbox Live Preview members but less than two dozen games are currently available. Microsoft promises that more than 100 Xbox 360 games will be playable on Xbox One when the feature officially launches during the holiday 2015 season.