@ChrisW GeoPackage does have backing of "big players". The OGC is a big player. Esri supports GeoPackage, and has done since 2013. I think it has plenty of compelling reasons over a shapefile: it does all a shapefile does and more, and better. It can be used 'anywhere', that's the whole point of it being based on SQLite. I genuinely can't get my head around it's current lack of uptake.

There's some information in a question here if anyone's interested: gis.stackexchange.com/questions/51862/…

@alpha-beta-soup If I start seeing requirements that specify GeoPackage in my work pipeline then I am likely to start experimenting with it. In the meantime, I'm time poor and there are many other GIS topics that are much more on my radar.