Since it is possible to program Emacs to do just about anything, I just adjust or fix whatever I need to and rarely look for the rationale of default settings.
(add-hook 'octave-mode-hook (lambda () (setq indent-tabs-mode t) (setq tab-stop-list (number-sequence 2 200 2)) (setq tab-width 2) (setq indent-line-function 'insert-tab) ))