Now that AdWords campaigns can no longer be split out by device, this leaves advertisers with a significant tracking black hole.
Tracking of AdWords relies on being able to split out targeting and then use tracking systems to identify which targets deliver the best ROI. If devices cannot be split out at any structural level within an Adwords account, then tracking solutions will not be able to identify which conversions came from a specific device. Now, web analytics packages will still be able to segment traffic and conversions by device but PPC software cannot. This could be quite problematic in specific categories that focus on device-specific KPIs.
One solution, which Google will no doubt advocate, is using Google conversion tracking. AdWords segment by device reports will still be available so by device PPC data and conversions can be found using this report alone. If advertisers need this level of data, they will need to implement Google conversion tracking otherwise face up to a layer of missing data.