Because all Classes can use Swift unless u dnt have OP to pay for it
Whilst all classes can link it, the benefit of linking it massively various from class to class.
For assassins Flash/Swift lapis is not needed to reach the max speed, and the only use of using them is to mitigate the effects of debuffs which effect attack speed.
For a spear wielding warr however, swift lapis increases their attack speed for the loss of a single slot.
Assassins are so far down on attack power that it is much more logical (assuming a debuff weapon build) to link a craft7 OR a debuff6 in the final slot of a weapon than a swift or flash lapis
Swift means that Hunters have more attack, more dex and more range than rogues.
Swift also means warriors have more attack, more theorectical dex (they have less in reality as 99% are full str builds too, but they could go full dex and still have higher atk than any sin) more defense and more HP than rogues.
And rogues are imo better off than casters
Swift is good for any class.
For orcs it gives max speed on wep and gives them bonus atk speed when debuffed either in SC pvp or in pvp with ground schock.Fast dispell and heal is always great to have
On Mages/pags it also gives big speed improovment which can also be very usefull for when debuffed and they dont need to use ice cream.It is very very annoying to have to buy over priced ice cream all the time and pop it every 9-10 mins and not to forget abbout it in some good pvp.
Imo, Swift benefits all classes the same, with speed.
Fighter(Warrior cant enjoy the max atk speed when debuffed while sin/orc and pag manny times can.
Same goes for hunter.
Also, /no support for removing swift (and i dont have swift linked in my 2h's and i know that others have advantage over me but still)