Every team is free to choose what works best for them, but IMO always squashing PRs is not a good strategy. Sometimes you do want to preserve the change history, particularly if the PR does more than a single atomic change, which in practice is very common. There shouldn't be a static merge type preference at all, and this should be chosen on a case-by-case basis.
At the risk of sounding judgemental, I think this preference for always squashing PRs comes from a place of either not understanding atomic commits, not caring about the benefits of them, or just choosing to be lazy. In any case, the loss of history inevitably comes at a cost of making reverting and cherry-picking changes more difficult later, making `git bisect` pretty much worthless, and losing the context of why a change was made.
At the risk of sounding judgemental, I think this preference for always squashing PRs comes from a place of either not understanding atomic commits, not caring about the benefits of them, or just choosing to be lazy. In any case, the loss of history inevitably comes at a cost of making reverting and cherry-picking changes more difficult later, making `git bisect` pretty much worthless, and losing the context of why a change was made.