Who builds a bike without a tensioner? Many of us do. If the frame allows it and you have a method of maintaining drive chain tension, like horizontal drop outs or engine shimming, there is no reason to run a chain tensioner.
There are pages and pages of discussion here regarding the pros and cons of that infamous device, especially the kit supplied item. There have been some very innovative methods used to keep the chain tight as opposed to that poorly designed clamp on thing that has caused so many problems.
Tom