Model helpers allow you to directly access a model from within a view. This is useful when creating things like select boxes that need data from anther model. For example, a Markaby select box for authors might look like:

  select do
    all(:user).each do |user|
      option user.full_name, :value => user.id
    end
  end

You could also use these within a view class to keep model-based logic out of the templates themselves. For example, in the view class you might define a method called authors that returns an array of name / id pairs. This could then be called from the template instead of the model helper.