I think LandDAO has good reasons for not accepting payment in installments because if clients are unable to meet the payments, it may have its own effects. However, in researching LandDAO, I found that one of their benefits is to make buying land easy. This led me to consider the idea of installment payments, which common people could also benefit from. But since they have mentioned no installment payments, perhaps LandDAO sells their land at affordable prices, as this may be the only way for everyone to buy land easily from them.
LandDao may not accept installment payment now but who knows in the future they may adopt the idea if they feel it's one way to reach out and get more people into their platform. One thing I have realize is that change is dynamic, for a project like LandDao they are ready to accept changes that will benefit them and increase acceptance. However, trust is necessarily here, I think that's more reason why they are avoiding installment payment. More reason can also be trust issues too, as most persons cannot keep to their words at the end of a bargain.