It depends, but generally: yes.
Beginners must completely internalize good habits.
"... but the safety is on!" is the worst possible thing a new shooter can ever say or hear. Whether she says it to herself or out loud, whether someone else says it to her or just acts as if it is true, it gives her a mental escape from the responsibility of handling the gun safely -- and that is not a good thing.
Well-trained shooters often emphasize the importance of training to disengage the safety every time they present the gun to the target. That's good. But far more important is engaging the safety every time the gun comes off target.
This matters because many guns with external safeties have very short, very light triggers. That makes them much easier to shoot well, but also makes them quite unsafe in the hands of someone who has not yet built good habits around the use of the safety.
A beginner (who may forget to put the safety on because they are just learning) is therefore probably safer using a gun designed to be run without an external safety.
(Details matter. Specific gun designs matter. This answer gives the wide outlines of some things to consider, and there are specific guns on both sides of the external safety divide that would be quite appropriate for beginners, as well as specific gun designs that are less appropriate.)
Looking at the Glock 9mm line up as an example:
G43 is subcompact.
G26 was originally called subcompact, but as a double stack it is actually more of a compact gun. Used with grip extensions, it shoots like a larger gun and gets near mid-size in handling characteristics.
G19 is mid-size.
G17 is full size.
Basically, step away from the very smallest and very largest guns in any company's line up, and look at what's left.
pax