I like it but I don’t like [name_f]Cassie[/name_f] at all (as a nickname for any name) so I’d personally only use with the nn [name_f]Poppy[/name_f], [name_f]Pia[/name_f] or [name_f]Sia[/name_f]. Having said that, I’d say [name_f]Cassie[/name_f] is more intuitive and would likely be used more (ie be an assumed nn).