Interesting question. Also interesting that top line manufacturers such as Rio embed loops into their fly lines and guys like Roman Moser recommend loop-to-loop connections. Also, furled leader folk recommend loop to loop connections.
My conclusion: it's such a minor part of the overall fishing situation so as to not make an ounce of difference what you use.
I use loop-to-loop connections all the time (fresh, salt, still or flowing) and it doesn't stop me catching fish.
Be careful what advice you read on the Internet: the blogger 'expert' you link to also recommends self-tied, knotted leaders using four-turn water knots.