Yes, it's a (reasonably) intuitive front-end for a lousy data format. Xlsx is supposed to be an 'open' format but it's overly complex and a PITA to parse. Like

Yes, it's a (reasonably) intuitive front-end for a lousy data format. Xlsx is supposed to be an 'open' format but it's overly complex and a PITA to parse. Like most things produced by Microsoft, there are a ton of unnecessary and overly-complex features added on that have little/nothing to do with data/calculations. External tooling sucks (because documentation of the format sucks). The additions that are supposed to support networking suck. The security features that are supposed to ensure read-only access suck. The file size of XLS files are unnecessarily large and not conducive to transmission over the web. If there was some way to reasonably decouple the data from all the formatting, object, validation, security, and scripting overhead it wouldn't be so bad to work with. Unfortunately, it's the most complex data structure manipulation format that 'business types' can reasonably understand so it gets used for anything and everything that deals with data and/or calculation.