I am not saying that bypassing the need to enter a password or PIN on boot or waking from sleep is a problem whether with a local account or a Microsoft Account.
[I do it with my Microsoft account, on the device that never leaves my house]
Blank passwords (which is not possible with a Microsoft account) are not a good idea, not only will it leave the device vulnerable but there are times when a blank password is not acceptable.
It is better to have a password and set it so that you don't have to enter it than to not have a password.
do not forget the password, there are some places where you must enter it (e.g. viewing other saved passwords in Edge etc)
Note -
setting up auto login, bypassing the need to enter the password or PIN boot, will allow anyone with physical access to the keyboard to access the data.
Blank passwords will a) allow anyone with the right expertise to access the device and data b) allow rogue software to use your account to do damage without being challenged for a password.