I have done both.

I only take one pair of shoes on a tour so if I plan to be more off road or do a lot of walking/hiking I do platform/light hiking shoe. If the main goal is to ride I do clipless/shoe with a walking tread.
For pedals I have either wide platform pedals with pins or the platform/clipless combo type. I like those as a bit of insurance in case something goes wrong with the clipless system or cleat.
I commute with platforms to work for the same reason - I only take one pair of shoes

I can definitely tell a difference between clipless and platform pedals in terms of not needing to think about foot placement on long rides. The same can be accomplished with toe cages/straps or those straps that go across the instep. To me it all depends on what the focus of the tour is mainly about. On high mileage tours focused on riding I also wear bibs and cycling jerseys. Imagine that!