actually strategically training game shape can be a real game changer
i have never done it myself but let me give you some examples i have heard from other (better) managers who have
1 - you are in a really tough division, week one everyone is in respectable game shape but you trained game shape instead of free throws or stamina in the first week of the season well you have a much increaced chance of winning your games in week 2 and 3 while everyone else slowly gets to strong and then proficient
2 - you are having a long cup campaign and despite some nice massages your starters are losing form due to the many minutes you have to play you want to do well in the league and the cup so you sacrifice one weeks training to give your team a little boost
3 - it is the end of the season and you really dont want to be relegated or really want to win it all and get promoted, lots of your players have respectable game shape due to injuries, trades, overtime games, other players fouling out, or just the coach playing them crazy minutes, so one week of game shape training and you are right back in the series
it is not a thing to do lightly your training is the most important thing you can do to improve your team but there are times when you may consider it
hope that helps