They do, those formats are a mess, full of small details and non-standard implementations on MS Office and Excel is most like the worst case. Office formats are all open until you realize that means shit because Microsoft does what they want and the standards don’t cover everything. If you’re serious about office and you need to collaborate with MS Office users those “other office suites” won’t cut it. You’ll have compatibility issues.
They don’t though? The file formats are documented and other office suite software can read and write them.
They do, those formats are a mess, full of small details and non-standard implementations on MS Office and Excel is most like the worst case. Office formats are all open until you realize that means shit because Microsoft does what they want and the standards don’t cover everything. If you’re serious about office and you need to collaborate with MS Office users those “other office suites” won’t cut it. You’ll have compatibility issues.