You need to check your math. It loses about 1.5 minutes per day on a naive implementation. Very few people left their computer running all the time in those days. (Also, it's pretty to fix the problem in software.)
But then how do you measure time since boot? With simple hacks like this of course. Also, this hack allowed a form of multi-tasking, an 8-bit feature quite well targeted back then.
Consistency was key in such clocks, not necessarily accuracy. The fact of the drift is not important, since it was consistent and could be accomodated for in software - as many peripherals of the day, indeed, required.