I had this app too, and I remember thinking it was weird because I think an official google developer blog (or something like that) mentioned the need to install it, as there was no built in QR code reader at the time. I can't remember which old phone I had it on though.

I also think those reviews might be left by people who can't find the original offending app because it's been removed. https://www.apkshub.com/app/com.qrcodescanner.barcodescanner seems to show it had BILLING permission though, which is always an alarm bell.

The one you're looking at on apkshub is definitely a different app. The version number, last update, and permissions do not match what is in Play.

The one on apkshub is the one mentioned in the blog. Google has removed it from google play. https://play.google.com/store/apps/details?id=com.google.zxi... is a completely different, open source app, with unexplained bad reviews, probably nothing to do with the malware, and hasn't been removed by google.