What are the pros and cons of wearing a robe vs a cloak (sleeves vs sleeveless)?
I used to larp and always opted for coats/jackets rather than cloaks whenever feasible. Here are the considerations I used to make frequently about outerwear, listed from highest to lowest priority for myself:


It is easier to add useable pockets (whether hidden or visible)
Fitted garments with sleeves are less likely to get caught in doors or get accidentally stepped on (eg. when ascending/descending stairs)
Fitted garments are likely to be warmer than a loose cloak in most cases
Fastening a jacket/coat etc is easier and more secure than most cloak fastenings
Cloaks are unusual in most modern cultures and will draw more attention than a sleeved garment, which may not always be wanted


I would like to add that a lot of these pros/cons rely on subjective opinion and context. 

I have some limited experience with sewing garments that have hoods, and have found it to be quite challenging to get the exact shape of hood that I want! I have found it comparatively easy to produce sleeves, so this is why I have not discussed whether sewing a cloak or sleeved garment would be easier, because in my opinion if you are making a garment with a hood, either option will be about the same difficulty.