In the sense that he was already familiar with the team and wouldn't have needed time to settle in like Cancelo has this season - yes. Walker's had quite a few poor performances this season and he could've been rested a bit more if Cancelo hadn't needed time to settle in. So I don't think we've missed Danilo tactically or whatever, but it would've been nice to have someone we could throw in there comfortably, especially in the first couple months or so of the season when Walker was playing nonstop despite dips in form. People will point to Danilo's performance at Newcastle but that was at LB and everyone played poorly that night; at RB he was very dependable - probably at the level that Cancelo's been at this season, but the difference is that Cancelo's actual level once he's adapted will be much higher, whereas Danilo's ceiling isn't anywhere near as high. Also he probably would've been given a go at CB by this point since Pep tried that out a couple times last season and in pre season this summer. So basically in a short-term sense, yes... but in a long-term sense, no, we won't miss him.
He is the greatest good luck charm in world football though. Not a coincidince that we go 11 points behind after he leaves ;)