Why are the bounding boxes in tlwh format and not in tlbr format?

[tuncalie]

I see that most operations convert given bounding boxes from top,left,width,height to top, left, bottom, right. One exception that I could see is the Kalman filter, which uses top, left, aspect ratio, height format.

Wouldn't it be more efficient to use tlbr format for the bounding boxes as input (or convert them to tlbr for once as as soon as they are provided)?
Please let me know if I am missing operations that actually rely on tlwh format.