My only complaint (other than I've always hated when they recycle maps from previous games) is that you need Internet connectivity to play these. That completely defeats the whole point of the Switch.
You don't need internet connectivity to play these, unless you mean downloading them initially. I'm sure they'll make an updated physical with these maps in it at some point too.
I definitely could not access them without Internet. This was after they had been downloaded and played. The error even said as much. Maybe they've changed that since? Hopefully...
Wait, what? Got a screenshot? Cos, let's face it, the switch has terrible wifi, and I'm frequently not on network and can play offline fine and have never had any pop up like that.
I'm pretty sure I have the initial free booster tracks and I was able to play them solo offline just like any other course. It has been awhile though, I could be wrong.