I have never read any of the books but my guess would be that Erle Stanley Gardner wanted there to be a bit of romantic interest. Also Paul Drake always liked her.
I read a good article in Sports Afield or maybe Outdoor Life in the early 60s by Gardner. It was about survival guns and he thought everyone should have a Smith & Wesson model 17, 6 inch barrel. I agree. It might have had a different name back then but the same gun, a .22LR on a medium frame.
This video has very poor quality.
The speed and sound track are way off.
But at 26:30 Benson Fong (in the role of Kow Loon) gives
one of the best dramatic monologues ever done on early TV.
https://www.youtube.com/watch?v=IZpKRrf6jI0
Just one of the fine performances that made the series great.
“I have never read any of the books but my guess would be that Erle Stanley Gardner wanted there to be a bit of romantic interest”
I have read a number of the Perry Mason books by Gardner but I don’t recall any romantic interest between the two. But then again that was like 50 years ago when I read them.
Watching the shows made me think about reading one of the books.