I think it will help with knee pains if you get the cleat right. you get a consistent 5* of float or more pending the pedal system. Vs un-defined range of straps pedal aka bear traps. I call them bear traps because if you need to unclip suddenly, your foot will never come out and you will tip over. Can be bad if tipped to the left into traffic. You might have the same problem for the first week when clipless until that habit of clicking in and out is formed. On emergency events, your feet will have a quick reflex to eject your feet

Aside from curing knee problems, you will get power through the entire pedal stroke, both up stroke and down stroke. Equals overall better efficiency by 30-50% = longer rides at easier effort including climbing.