Friendly matches are part of the matches that are difficult to predict. Just like you have said, it adds nothing to the team. Don't be surprise if the underdog win the match with their big odds. I do catch cruise with games like this sometime if I have some extra cash. I will just pick like 5 friendly matches in which I will place bet on the underdogs individually as a single bet. If just one of the game win then I still win big. Although this is risky but worth trying once in a while with little money that you can avoid to lose.
Losing and winning are the outcomes of every match played. We try our best to have an accurate prediction regarding these matches, they're friendly matches? I do stay away because I don't want to get shock by my prediction concerning this friendly matches. They're consider harder than the main fixtures, I know few matches that are friendly and I've taken the risk to bet on them, guess what, my prediction failed because a random average clubs defeated an almighty elite team, how is that even possible to begin with? Based on my past experience I no longer deal with these matches because they're consider no serious match.