For better or worse I created a very similar system, but using Google Sheets instead of Excel files and fetched with the GSheets API. In that case the configuration was gigantic (many of the configuration values were product-decisions, and it ran in hundreds of different environments with different tweaks), so the tabular structure made navigating things very natural. It also had the advantage of structurally highlighting how environments differed. Doing it with Google Sheets came with some extra nice benefits: online sharing, versioning, access control down to specific ranges, etc.
Basically every engineer who joined the team thought it was a unforgivable blemish on the system, yet it survived a few years with no major issues, long enough for the team to build an internal backoffice and port the whole sheet structure into a proper CRUD API.
Basically every engineer who joined the team thought it was a unforgivable blemish on the system, yet it survived a few years with no major issues, long enough for the team to build an internal backoffice and port the whole sheet structure into a proper CRUD API.