Can they use the freedom trink to escape those?
Yes, But they can use the trinket on fear also.
Mostly it can be used proactively and strategically whereas rooting only works if they are already in your face.
It eats a fear ward.
You can slip out of LoS, cast out of range of melee, slip back behind your cover, and it still helps your team.
It will still hit players that were LoS when cast but engage a second later. ie you stopped the warrior that engaged you first, and then you stopped the mage that entered the room a second behind.
Players can still cast when rooted, they can not cast, throw. Etc. when feared.
Some skills get out of root, fade (with phantasm) and dispersion for example are two skills another spriest can use to get out of a root and then they still have their trinket.
Warriors can break a fear, but they can also kill the VT. If they break the first fear, they can’t break the second without burning their trinket, leaving you with your third fear if you need to use it.
It is really useful when pillar humping. You cast it, run around the pillar for LoS. Someone else picks up the chase, but as you round the corner again they get hit by the Psyfiend you cast a few seconds ago.
You can place it and it will continue to be effective as you run to your objective. i.e place it at a choke point and keep running.