Yun po ang problema they don't, I think it's because masmadali siya ma implement hence we can safely assume they don't care or hindi lang sila marunong. Yung OTP rin nila, it lasts very long at walang timeout, wala rin rate limit. That's a problem kasi anyone can bruteforce it easily kahit code payan basta lang may limitation yung pattern at computable.
"the user logs in nag sset na agad ng token or cookie to verify the account and otp which is uneccesary" Not really po kasi if you verify the code, the system still needs to know para saang account siya or anong account ang ilogin afterwards. Yun lang, nag diretso sila at binigay agad without limiting yung hindi pa na-verified OTP token.