We can turn ours down to low enough to simmer but that introduces the very common problem of the flame being very readily blown out by drafts through the boat
. So while we get by without a diffuser one would probably still be the best way for us to go but while I have never had a serious search I have never noticed them in the stores here so haven't bothered.
, the main point being, even if ones cooker can be turned down enough to simmer, it may not be much help so I wonder if its not being able to is done on purpose and for safety
(even if one does have thermocouple flameout protection).