In some ways, such information is just as important as biometrics and passwords and pii.
Deanonymizing becomes possible when metadata is cross-referenced. Metadata should be subject to as strict protection and consent rules as documents, health info, or any other "obvious" private data.
If it's running on your server and not logging third party activity or metadata, the information belongs to you. Else, you need the third party's consent, etc.
"It's just for benign development purposes" doesn't cut it anymore regardless of intentions. We need a cultural and legal area change with regards to privacy and primacy of private data protections.