Thats actually a smart approach if you look at it from a controlling aspect. Slot game sounds are designed just like most gambling apps to trigger emotional responses, near-miss beeps and big wins noises are all cues that keep players hooked. Turning off the audio can reduce that constant stimulation, making it easier to step back and play more deliberately. even if the visual is still there alot of the addictive pull comes from sound so removing it could help curb the urge to keep playing.