It’s totally normal to use hose clamps in this situation. This a PVC to Cast Iron connection. That’s the only way to do it.
The small clean-out is kinda fucking dumb though. And the big hose clamp looks like it’s installed wrong. Can’t possibly be tight enough and be at an angle like that.
Oh yeah, that I agree with! I’ve had good luck with OEM rubber hoses from LG in the past, but have since replaced them with stainless steel braided hoses indeed!