This is just a pre season friendly match. We have seen Manchester United performed very good in pre season matches in the past and crumbled during the season. It's good that they have won two premier league teams in their pre season matches, but hope they can win them where it matters. I would prefer them losing in the friendly matches and win in the league matches against these two teams they have played so far.
Winning preseason matches doesn't guarantee a team will perform well in their domestic league. Yes, Manchester United had won all their preseason matches in the first season of Erik Ten Hag as Manchester United head coach, but Manchester United failed to replicate what they did in their preseason matches in the Premier League. I am okay and happy Manchester United won their last 2 preseason matches because I believe it will boost their morale and make them believe in themselves to compete in the Premier League next season.
You have said it all, I see pre season matches as just a medium for which players in the team, both old and new need to familiarise with each other and create this type of bonding that's going to serve them for the rest of the season. Even though pre season matches results doesn't matter that much, but the training is really beneficial to the team. Any team that has a good pre season time, often go far in the league. Unless the team get hit by injury crisis somewhere along the season. If am being sincere with myself, I love how Manchester United has done their business so far with their pre season matches.