[SOLVED] What is the point of Object#presence in Rails?

In the Rails docs, the example provided for the Object#presence method is:

region = params[:state].presence || params[:country].presence || 'US'

But isn't that just equivalent to:

region = params[:state] || params[:country] || 'US'

What is the point of using presence?

Here's the point:

''.presence
# => nil

so if params[:state] == '':

region = params[:state].presence || 'US'
# => 'US'
region = params[:state] || 'US'
# => ''

What's more, it works in similar way (that is, returns nil if object is 'empty') on every object that responds to empty? method, for example:

[].presence
# => nil

Here's the documentation, for reference: