I suspect 5GB isn't going to go far with today's data usage but still, it's good enough to at least get somewhere with Wi-Fi (or a place where you can get a local SIM card) after you land.
What I'm more interested in is the in-flight Wi-Fi benefit. If it's usable on some of the newer Wi-Fi services (e.g. ViaSat) that would be pretty big depending on what airlines one flies.
EDIT: per
their site it seems some/most AS, DL and AA flights will be supported to start.