The whole point of having an outrigger (one side or both) on a kayak or other slim width watercraft is stability

 Outrigger canoes and sailing outrigger canoes

When you have the stability of one or two outriggers you can have a much thinner width boat which means it can usually travel faster with less resistance to the water around it. So, having this stability allows you to go faster in most situations. 

However, in a storm you might not want to be in an outrigger or catamaran or trimaran because this might not work to your advantage in storms that much. But, most of the time the catamaran, trimaran or Outrigger idea is a good one (most of the time) under most lake or river or ocean conditions.