They are actually slightly different tenses, so whilst they are the same in English they wouldn't quite be the same in Gaelic. You are wanting is a more accurate translation of how this phrase works.
It doesn't make a difference yet but I imagine they have done this to prepare people for when it does. For example the phrase tha mi a' suidhe and tha mi nam shuidhe both mean "I am sitting", but their tenses are slightly different. Tha mi nam shuidhe is more like "I am seated".
So translating this is "I am wanting" is to prepare you for this.
It’s because it’s a more precise translation of what the Gaelic is saying.
It’s literally “are you at wanting a jacket”, with a more useful interpretation being “you are wanting a jacket”. The use of expressions like “I am wanting”, “are you needing”, etc, is common in parts of Scotland (I hear it regularly across the Highlands and Outer Hebrides) and parts of America populated by descendants of victims of the Clearings (for example, it’s VERY common in Appalachia, at least from Georgia to Kentucky/West Virginia).
More info from the course tips/notes (search for “verbal nouns”):