birth control continuous use

lyss

i read that while on birthcontrol (combination pills) that you don’t grow a uterine lining to shed and that your “period” it simply withdrawing from the medication.

so it says there is no harm to continuously take your birthcontrol pills and basically just skip the period all together .

so for 1 is this true / safe?

and 2 why do we take placebo pills then ? why do we get told to have a monthly period still if it’s not necessary?

i was just researching this because i wanted to delay my period for a few days . but i went down the rabbit hole .