I think all fly casters should work toward casting at all rod angles. Not only that but the should also learn the high elbow cast AND the oval constant tension cast. There are airealized casts and then there are the variations of the roll/spey casts.

I think that is part of the natural progress of a fly fisher as the needs of presentation determining the best cast for the situation.

Here is a example. I was the rear fly fisher on a float boat. We were facing downstream and fishing the left bank. The situation demanded a low sidearm cast. To cast sidearm without hitting the rower, you have to face towards the stern of the boat.

On this cast, the cast had to be overpowered so that the fly would land with an upstream curve to prolong the drag free drift.

For Lefty Kreh that would be an easy normal left handed sidearm cast with a little extra power on the power snap.

But I am a right hander. From that position, there are two ways a right hander can cast sidearm.

I could have casted with a right handed sidearm, with my forward cast toward the middle of the river and the then the backcast being the delivery cast. But like most fly casters, I have more control of my forward cast, especially when I need and overpowered curve cast. So what to do?

I decided to make both the cast toward the center of the river and toward the bank, forward casts. The way to do that is to make the cast to the center of the river normally with the casting hand supinated (palm up) and then pronate the palm (palm down) and make another forward cast. By rotating the casting hand and wrist between what would normally be the normal alternating forward and back casts, you can make both ends of the sidearm casts, forward casting motions. I then had more control of the downstream curve of the delivery which gave a longer drag free drift.

Of course if you PRACTICE this technique you will be more effective when it is needed.

This method of making linking two forward cast is not unusual. in fact, I got the idea because I was familiar the the Galway cast. The Galway cast is a the same type of cast but done overhead. I've used the Galway plenty of times on my local stream when my backcast has to be into an opening between trees on a stream bank.

Basically the cast I did was a sidearm Galway cast.

Galway Cast – Fly Casting Video Masterclass

Incidentally, the Galway is part of the cast that Jason Borger did on the "River Runs Through It"

the Shadow Cast – the limp cobra