This is due to the fact that id can’t be decided automatically if you don’t pass the model instance.
One of these two should work instead:
julia> model = StandardABM(MonetaryActor);
julia> MonetaryActor(id = 1)
MonetaryActor(1, Set{Symbol}(), Function[], Dict{Symbol, Any}(), Balance())
julia> MonetaryActor(model)
MonetaryActor(1, Set{Symbol}(), Function[], Dict{Symbol, Any}(), Balance())