But more importantly, you would have to redefine the length of a second in order to keep days the same length. Redefining the length of a second is not good. Really, no.
Then there is the problem that this is not really a sensible metric time – 10 hours, 100 minutes and 100 seconds each? Frankly, that's stupid – ideally, you want the conversion factors to always be the same, ideally 10³. The swatch time mentioned above got this right with 1000 minutes (‘.beats’)/day, if absolutely necessary, you could probably also go with 100 quarter-hours/day and 100 seconds/quarter-hour, with 1 new second = 8.64 old seconds, or 1 old second ~ 0.12 new seconds.
The underlying problem here is that time lengths are intrinsically non-metric and there is little to no way to consistently make a year and a day both ‘metric’, simply because nature doesn’t require them to be. The same goes for nearly all other SI units – the equator is 40 Mm, the average height of a human is ~2m, a human weighs 80kg, not 100kg (and really, kg as the base unit?!).