Trading days that equals more profit is not real. Anyone who tells me that they are more profitable because the trade on specific days of the week is not telling me the whole truth. Being so successful trader has nothing to do with the days you trade but skill, knowledge, experience, grit, emotional intelligence, trading psychology and other important factors all combined together to make a trader successful.
Trading excuses like this are just a funny joke and an excuse for not giving one's best.
It might work for some because they believe in it but they can't say they always make profits every week that particular day, you can't always make profit everytime you trade no matter the amount of knowledge you have so you can't always guarantee profit every particular day of the week. And also having to wait till another week to trade is actually not so ideal when you don't know when your lucky will be. With the right amount of knowledge you can always trade when you want if you know what you're doing.
Just have a good trading strategy and follow it properly you don't have to always have a special day to trade, IMO you will miss out on the wonders of the market on other days. Also you have to have in mind that losing in trading is inevitable.