The potential to profit far exceeds any other incentive to trade. Any "manipulation" is simply an attempt to make profit...just like every other trader in the market.
Come on— Someone who executes trades at odds with their own beliefs in the valuation of the good in order to trigger software or psychological bugs in the other people on the exchange is a manipulator. They are fairly called a manipulator rather than an honest trader not primarily because they trade on N-th order effects but because they _reduce*_ the efficiency of the market rather than increase it.
*(you can argue that they increase it long term by hardening the counterparties to these attacks— but the hardening wouldn't be required if the manipulators didn't exist, and the induced inefficiency today is very real while the increase in long term efficiency is more speculative)