My LO turned to 4 months yesterday. She loves TV, when we put Barney the dinosaur on Youtube, she can be watching it with no problem, I can leave her for over 2 steps away, which I can't most of the time. So I try to limit screentime when it's really a massive help, as apparently it's not good until 18 months.
My daughter is exactly the same and turned 12 weeks in recent days. Some might disagree but I think it can be a sensory experience for them. I put on Disney films or bright colourful baby friendly shows. Like you said, it’s not on all the time so I wouldn’t worry about it. X