As the article mentions, good fabrics (like merino wool) can go a long way.
(1) Reliability and flexibility being foremost. Not having to worry about lost luggage. Itinerary changes are much easier when all your stuff is with you and can fit on your lap or under your seat. Then comes the comfort and speed. Being able to take the stairs or not blinking an eye at walking an extra half mile go a long way towards making travel enjoyable.