Thanks for the question @tastrax and @micmin1972!
(In Estonia where I come from, we have a saying that there are no dumb questions, only dumb answers )
The orange dots represent what you could call "curated sequences". These are some of the really great recently uploaded sequences. "Some", because our team, as much as we'd love to, doesn't have the resource to go through absolutely all uploads, so we might miss some good ones (which is why we encourage people to share their own with #MapillaryExplore). So exploring those sequences offers a chance to both see amazing places and also get an idea of how great a Mapillary sequence can look.
Because next to the "something is better than nothing" motto that is super relevant in terms of obtaining data from photos, it's still great to strive for excellence if possible, with well-lit non-blurry photos that have no car hood / bike handlebar / human fingers etc. in view and have been taken consistently enough to allow really smooth transitions from one to the next. You can call it the Mapillary eye candy