In noisy settings, listening with a hearing loss is often quite challenging. In the figure, listening to speech in noise is similar to trying to read the word "speech" printed in the top box.
Adding a hearing device with noise reduction and directional microphones can make listening noise easier and more accurate, much like reading the word "speech" in the middle box is easier because it is more distinct from the background.
Although technology can improve the situation to an extent, substantial room for improvement remains. Watching a talker's face adds even more information and can greatly increase the ease of understanding speech in noisy settings. The amount of benefit depends on multiple factors. Lipreading ability is one of those factors. Better lipreaders tend to obtain a greater benefit.