I think this is because when you participate in the program for 12 months, the user receives the largest percentage of profit.
When people lease tokens for 12 month they have a bigger profit but the risks are bigger too because the market conditions can change during 12 month.
Everyone chooses a path in investing. If you do not believe in this or that project, then maybe you should not invest in it.
It is also possible to lease the tokens for 3 month and 6 month but people prefer to lease for 12 month. It is very risky because cryptocurrency market is very unstable.
The market may change tomorrow or maybe in an hour. There are always and always will be risks.