Jinja is a text engine, not all data is text, when something a bit more complex is being used - a lot of problems appear all of the suddent, e.g. jinja spacing issues when you want result to be dict or list. Coertion from text to other data types (implicit in old ansible-core versions, explicit in new versions) is also kind of a problem, I prefer to be sure that I work with “native” data sctructures.
Some more arguments are in this thread
(How to solve ansible challenge from ansible-core maintainer)