Using a sentence starter to transition from body to conclusion is abrupt and choppy. A skilled writer should be able to do so without one.
Though if you're not a skilled writer, it might come off better with a starter, or else the text will end as one block and the readers will have to figure out themselves where they're at, which is not recommendable.
Nicho is right that in scientific papers you absolutely don't need starters as the structure already makes it crystal clear what is what. Such structures are not found in essays and thus have to be replaced somehow, be it with layout and/or starters/formulations.
