I am actually surprised by how many hot takes are in this thread. Simon is a great complimentary player for the right line. Sure he doesn't have the finish to be considered top 6, but he did all the little things that Sid liked, so that is why he played with Sid. His possession numbers are likely amongst the best in the league, so yeah it sucks that he doesn't score, but he at least helps the team by keeping the puck. Likely the main reason the Pens didn't resign him is that they are hoping that Kappy can have similar possession numbers, but with much better finish. Simon would be great on the third line for most NHL teams.
Bennett can be frustrating because he does a lot of things right, but his regular season numbers don't seem to be there. However, if you are a team that is likely to make the playoffs without Bennett producing, then why do you care? He is a beast in the playoffs and if your 3rd line can put up solid numbers, than you have a solid base for a team to go deep. Bennett has not been the reason the Flames haven't had playoff success. That blame goes to the top 2 lines and the lack of consistent goaltending. This offseason, they hopefully solved the goaltending issue. The problem is that Gaudreau and Monahan don't seem to be playoff players and Tkachuk makes himself such a target that he will likely always be battling injuries come playoff time. Not to mention that the refs will likely ignore a lot of the cheap stuff against Tkachuk.