Inspiration never really came up often in my group. When we first started my GM did give us some inspiration after boss fights, but afterwards we generally did well enough that we didn't need them. That being said because we don't have get inspiration I did sometimes forget I had them and never used them, but the one time I [i]really[/i] needed a reroll, I remembered about it and it saved my life. So inspiration can certainly be helpful, but I don't think we really need it. If we play smart we don't need them, but I do feel like they would be a nice little reward after particularly difficult moments.