Most would consider it standard advice for any tech not just specific to Microsoft. and the advice is given because I do consider the individual situations.
The danger is there, if you go online or if you download files, open spam emails, or basically do anything.
And again This is The Microsoft Community and is probably safer than any other website. and again, nobody in the Microsoft community can access your computer with or without a password
Local groups are less of an issue than the web other than of course you have no control over anything they download or install especially if they too are silly enough to have blank passwords on their devices.
In your own house with only people you trust, it is enough to turn off the need to enter the password on boot or waking from sleep - this will only give access to people with physical access to the device. but will still prevent bots on the net accessing your data.
As I said this is what I do using my Microsoft account on devices that do not leave my house.
Having a blank password will give access to anybody including those on the net when ever you are connected, this may be as simple as stealing you data, or they could have access to installing other software.
Blank passwords are not a good idea on any device whether it is android, Mac, Linux, Microsoft or some other OS.
It is your choice if you are happy to leave your device vulnerable, it is irresponsible to give that advice to others.
Of course nobody has to take my advice :)