Hello from the Docs team! Thanks for flagging this issue. We discovered the issue in durable code snippet was the inclusion of <final> . We’re getting it fixed and republished today. This was also the only affected snippet, the others should compile correctly.
With regard to the differences between the snippet and feature example, the code snippets are intended to provide a simpler examples of setting up your entitlements and show the pairing between an entitlement and its descriptors as clearly as possible. Additionally, because these are snippets, the using statement is not required because the entitlements are not defined in their own module.
In case you missed it, today we published the new > In-Island Transactions Device Template doc, which goes over the Verse device template in more detail. Hopefully that helps alleviates some confusion. Thanks for your feedback and flagging this issue!