I feel like trying my clumsy hands on motor (car, not bike) racing sim with no steering wheel but HOTAS. I can easily guess immersion wouldn't be the same but is it really a crazy idea?

It's not crazy for starting out, but you are correct in thinking that the immersion is not the same.

For sweeping turns it becomes very difficult to hold a constant steering input, which results in a lot of weaving. It's frustrating.

Not at all. Years ago, quite a few sim racers used their joystick for controlling the cars. I tried it when I first started out but I quickly realised that I was so bitten by the racing bug that I just had to have a wheel.

Thanks for the input. mates.

I'll give it a go..