That is true, but having nearly a million entries on options table isn’t something what was intended ??
besides to info stored in there is mainly used by wc anyway, so i think “reinventing the wheel” would make a perfect sense, in case u have lots of products like the site i came across. this would at least not hamper wp core and other part’s access to options table.
Also, it would be nice to have an way for wc to auto remove expired transients, for example via a cron/scheduled job that could run every 3 day or so. that would be very helpful.