You need to define the plot type for which you define the convert_arguments:
Makie.convert_arguments(S::Type{<:Scatter}, ::Foo) = convert_arguments(S, rand(10))
You need to define the plot type for which you define the convert_arguments:
Makie.convert_arguments(S::Type{<:Scatter}, ::Foo) = convert_arguments(S, rand(10))