One of the major benefits of low carb is that it lowers your blood sugar and your insulin response and allows better access to stored fat. If you are insulin resistant, it can make all the difference between losing and maintaining (or gaining).

If you are insulin resistant, eating low carb for two days, lowering insulin response, then eating higher carb again may leave you with high blood sugar following then low carb days, and possibly reactive hypoglycemia as your body adjusts to different carb and insulin loads.

If you are relying on ketosis for weight loss, cycling between high and low carb could leave you in a situation of constant adjustment (aka Atkins flu) - ugh.

Myself I find I lose best if I eat in a consistent manner. I used to be insulin resistant but after nearly 10 years of lower carb, my insulin is now in the low normal range.