Hanigan did a lot of "work". That's his thing. To the casual viewing, flashy always gets eyeballs more than work, but that might be why he got some votes (they'd have had stats on work-rate at hand). But I thought Staniforth, for example, probably had more impact.
Personally I look at impact on a match - how did they change the game. Hooper just did a shitload of work (impact), hard to say Ramm had a huge impact but was good in his role; Hanigan solid but not flashy (not huge impact I reckon). I actually thought, value for time-wise, Hunt was in the top 3 for the Tahs. Big impact for the time on field (irrespective of potentially dodgy 50/22 calls!).