Wii Play and Wii Sports actually have very distinct arcade gameplay. Wii Fit more or less does with it's balance games.
Arcade gameplay refers to the type of game you would see in an arcade. They would typically be easy to pick up and play, addictive, and competitive with high score lists and local multiplayer. In terms of progression, it was always kept short and linear, with very little in terms of new content. This was all, of course, to make sure those machines got all your coins.