Why are sqlite3 shortcut functions called "nonstandard"?

I've used sqlite3 in Python in which execute() creates ambiguity. When I use:

import sqlite3
A = sqlite3.connect('a')
A.execute('command to be executed')
help(A.execute)

I got the output of help() as:

.....
.....
Executes a SQL statement. Non-standard.

But when I execute like this:

import sqlite3
A = sqlite.connect('a').cursor()
A.execute('command to be executed')
help(A.execute)

I got the output of help() as:

.....
.....
Executes a SQL statement.

My doubt is what does Non-standard refer to? Even the Python documentation provides these words execute for execute(), executemany(), and executescript() in connection objects.

I've even searched in web about nonstandard shortcuts in Python. But I didn't get any relevant information. Can anyone help me with this?

from Why are sqlite3 shortcut functions called "nonstandard"?