You have to factor in the amount of money you win and the amount you put in yourself. The more players/money in the pot, the better for you if you're 40%
Because if you're headsup with 2K in the pot and you put 1K of it in, but you're only 40% equity, then in the long run you'll win $800 for every $1,000 you put in, thus winding up a net loser of $200 each instance over time.
But if there are three or more players in the pot and you have 40% equity, you're going to realize a net overall profit because of it.