> This format is even less wieldy than the current one, requiring multiplication and division to do basically anything with it, except string formatting and parsing – once again showing that MySQL places too much value on string IO and not so much on having types that are convenient for internal operations and non-string-based protocols.
Not necessarily an odd choice in the Olden Days, after all BCD representation used to be pretty popular. By modern standards it's insane, but at a time where binary to decimal conversions could be a serious performance concern it might have made sense. For instance if you had a date in "hours, minutes, seconds" and wanted to add or subtract one of these TIME values, you could do it without a single multiply or divide.
Now I was 8 when MySQL first released in 1995, so I can't really comment on whether that choice really made sense back then. 1995 does seem a bit late for BCD shenanigans, but maybe they based their design on existing applications and de-facto standards that could easily go back to the 80's.