I don't think it's a signing for the sake of it at all.
There's a good book: "Sven-Goran Eriksson on Management" from his time as England manager, I think a couple of other people on here have mentioned they've read it too, where he talks about his approach to management. One of the main things he says is that he tries to guard against complacency, by putting pressure on players in the first team by having a strong squad rather than a stable XI. His approach is that you should put more pressure on a team when they are in good form and less pressure on the team when they are in poor form. He tries to make sure players know that no one is a guarantee for a starting position. He also says he thinks the common adage "never change a winning team" is a load of bollocks.
I think he's genuinely trying to build a squad with 2 or 3 good players in every position. Berner was always going to be surplus to requirements, he showed last season he doesn't have the legs to play as attacking full-back as SGE wants, he was great for us under NP when much more defensive full-backs, who didn't need so much in the tank were used, but he just doesn't fit in with SGE's gameplan, same with Hobbs, it's just what happens sometimes when you change managers. Doesn't mean he's a bad player who won't work somewhere else, just that he's not going to do it as part of this team.