To call it 'more cautious' is a bit misleading, even if correct on a technicality. If our wingers are attacking and Gross is pushing forward, it's not particularly cautious.
That's how I see it too, and why Gross had such a good game against West Ham. Izzy has been a great help, we just need March and Knocky to step up.
Of course I could be wrong, maybe he was just being lazy before and decided to make an effort because there was new competition for his place...
As you say though, we'd expect Gross to start. A winger swap is standard affair. Of course it depends how things have gone in training, but I'd think Locadia would come on in the second half, unless we're losing and Swansea are sat back, in which case Chris might choose height instead.
But Gross is more likely to help out in midfield than Locadia isn't he? Gross will be between midfield and the front man, whereas Locadia is more likely to be one of two front men (at least it looked that way against Cov).
That doesn't mean Gross is a cautious pick, but Locadia is even more...