It means very little without context. I’m 6’4” and my wingspan is 6’7” and I don’t have long arms. I have a big chest and broad shoulders, my frame is like a giant (260lbs) J.J. Reddick. A slender 6’4” NBA guard w 6’7” wingspan will have much longer arms and critically he’ll have a much higher reach. For bigs especially standing reach is much more important. Wingspan might be more important for perimeter players but with them as well, standing reach is more telling.