guess is that they are trying to pull you, but in the event the pull doesnt work the cost is refunded, but it also gives them major expedition for a time too

free cast if your cc immune + major expedition, is my best guess

not like it seems to do a lot of dmg if its only hitting for like 2-3k

other context is missing, like if this was done by a single person, or if it was a zerg because your also taking dmg from a sorc and NB in there too, and the total time of the fight that was registered

pulls are effective in cyrodiil mostly because they can either separate you from a group, or desync you

It does amuse me when I see threads in the main forum about 'niche PVPers' etc...in my experience Cyrodiil is full of PVE players doing everything they can to avoid PVP, such as sieging empty keeps when other factions are asleep or spamming chains from the back of a zerg.