Just why would you set a buyout clause so low?
Asking for trouble really.
For smaller sides it gives them a realistic chance to sign good players, by giving them an escape clause if they play well for 12-18 months then they'll move on because A) they've played to their potential or B) a bigger side has seen enough to take a punt.
When it works out for both sides is when good player fires them up the table after signing/being released from bigger club. Instead of finishing 14th, they finish 7th, all parties are happy and good player gets to use the smaller as a stepping stone back to the bigger clubs.