Since Excel 2007, Microsoft has split the classical .xls format to several formats (in particular, .xlsx, .xlsm, .xlsb). I've got no problem to understand the use and purpose of .xlsx format but I am still wondering whether we should use a .xlsm or a .xlsb format when creating a file containing some VBA.
Of course, you can find some topics on the web, for instance:
.xlsb)What I've understood from this last link is that .xlsm is some kind of XML format and thus, needed for custom ribbon tab.
Beyond the conceptual difference between the format (.xlsm is based on XML VS .xlsb is a binary file), is there any practical difference when using any of this file (apart from the ribbon customization)?
Have you ever seen any real difference when using any of these formats?
They're all similar in that they're essentially zip files containing the actual file components. You can see the contents just by replacing the extension with .zip and opening them up. The difference with xlsb seems to be that the components are not XML-based but are in a binary format: supposedly this is beneficial when working with large files.
https://blogs.msdn.microsoft.com/dmahugh/2006/08/22/new-binary-file-format-for-spreadsheets/