It's simple. Body of work refers to one's accomplishments throughout their career (trophies, season awards, points, etc). The HOF often makes decisions based on a player's body of work. This is separate from a player's skill level and abilities on the ice. When comparing players, it is always more logical to compare their skills (skating, stickhandling, shooting, passing, etc). I quite honestly do not care about a player's points or accomplishments because they depend on many things (linemates, team style, ice time, usage, commitment to defense, etc). However, I do appreciate a player's absolute skill level having played ice hockey growing up. When comparing two players (X is better than Y), it always comes down to comparing the individual skills between the players, which are independent from other factors like linemates, team style, ice time, usage, etc.
When I am comparing Petro to McInnis, it comes down to what they can do on the ice (skating, stickhandling, shooting, passing etc).