Very worth it to play for free - you get hours of free content and the class story is great. Also the game's very friendly to playing alts, so you can play out the class stories with different story Light-Neutral-Dark story choices. Some of the class stories have different endings as well depending on your character choices.
There is also this one line " Upgrade to a full Guild Wars 2 account to unlock this swift and agile companion permanently! " which is different from saying "Buy Path of Fire to unlock it permanently" as another line claims " To further train the raptor's mobility and combat skills, accounts must have the Guild Wars 2: Path of Fire expansion Accessing guild banks Buying dyes Not as many character slots (2) compared to (5) With heart of thorns rocking up, You won't have access to; The new maps The new specializations The revenant Guild Halls Any of the new mastery systems; gliding, Legendary gathering, Legendary armour, raids.