Is there a performance benefit to writing a Kibana plugin vs. a standalone application?

We're currently evaluating a new UI for one of our systems and it's potentially possible to do everything we want to do in a Kibana plugin. We're also evaluating building it as a standalone application outside of Kibana. This UI would potentially need to query a lot of data from Elastic. So the question is... is there a performance benefit when using a Kibana plugin? Does it have the ability to query the data faster because it is more tightly coupled with Elastic? Or is it basically just using the Elastic APIs (just like our standalone app would), so there's really no performance difference?

Is there any other reason why we would choose writing a Kibana plugin instead of a standalone application?

By writing kibana plugin you get some of the things for free, like connecting to elastic search, handling security etc. You also get index patterns with scripted fields and field formats, and access to other kibana services. Also there is some level of caching build in kibana (and will probably be extended in the future). However when it comes to connecting to elasticsearch we are using elasticsearch-js client, which you would probably use in your own app as well (if its js based) so i don't think there would be any performance benefits there.