There are so many functions and values delivered by Excel that it is not something I could or plan to escape from soon . Having said that, Coda delivers lots of spreadsheet functionality, that because its delivered in the context of a Doc, makes it a lot more valuable for so many use cases than Excel.
So, rather than escaping Excel I would suggest adding easy embed support (already in the Suggestion Box with many votes) and develop a Pack to sync to Excel Tables. There are many use cases where this two way sync will be a valuable addition to Coda and the millions of users like me that have Office 365.
Aside: Microsoft is building its own component doc solution with the advent of the Fluid Framework that will no doubt leverage Excel ranges, sheets and workbooks in many innovative ways. The Fluid PM at MS Build 2020 mentioned they have 185 member team on that project so far.