The reason I chose the 24L was because it was the widest angle 1.4 to use on my crop camera. The 35L would have been 55 mm FOV on my crop camera, that was not wide enough for me. I was used to using my 17-55 zoom at 2.8
I found the 50 mm 1.4 to be too tight on my crop camera. It makes a nice portrait lens of one or two people waist up. And it is a great lens for the price. But many times I found myself indoors not able to back up and get the shot I wanted the 24 else solve that entirely.
Yes the 24L is expensive, but once I used it on my crop I fell in love with it. And now I'm full frame it is even wider, I will never sell it.
I justify the cost by using it so often. My 50 mm gets the least use if you are wondering. It's just so close to my 40 mm STM and the 40 weighs nothing.
The 35mm IS 2.0 is another great lens but it can't do 1.4 when you need to keep a fast shutter and capture light in those concerts.