Someone has to be able to maintain it. What happens when the one person who understood it leaves and it needs to be modified or upgraded, if they're lucky they can hack it into working and even that's not a good thing as the build has now been modified in a way that is not understood and possibly broken. If they can't figure it out and the need is not that strong they'll leave it as is and just not change whatever they originally had wanted to, ultimately limiting themselves and their solution in someway. The last choice for them is do the only thing they should when there are components that are not understood or can't maintain and rip it out and in the process lose many days or weeks replacing it.