If it was purely a cost of bandwidth issue they could easily limit the size of downloads. Most projects on Google Code only need to offer downloads of a few MB

If it was purely a cost of bandwidth issue they could easily limit the size of downloads. Most projects on Google Code only need to offer downloads of a few MB in size to fulfil the basic need. It's really hard to imagine that being a significant cost to Google, and the convenience of having downloads integrated into the service is huge.