Too many "features" that makes it possible for the user to accidentally render the whole thing unusable, e.g. trust center can disable basic functions such as saving by checking checkboxes, and are sneaky enough to evade search once set. Also, there is no simple "back to defaults" shortcut that undoes such disbilitating damages. You'll have to dig and guess and google for why it suddenly breaks.
As Windows forces new updates onto you everyday, probability that you wake up one day to find your old documents unusable approaches one.
Since it has become Microsoft policy to plan for its "outdated" (but working) software products to expire and replaced by "up-to-date" (but prone to failure) replacements, one day we'll have Excel too complicated to perform simple functions that many use VScode plugins instead.