This article is specifically talking about the use of hydrogen blended into natural gas pipelines as a way to reduce dependence on fossil fuels for heating and cooking. Ammonia as a transport mechanism has no place here.
The current consensus in the industry is that you can replace up to 20% of the natural gas with hydrogen in a pipeline with no adverse affects. This article is indicating that there may in fact be some adverse affects.
Edited to fix some stupid autocorrects. At least it was mainly verb tense this time.