All your cocks are therefore synchronized to UTC anyway: it would mean you’d have to translate from UTC to TAI when you store things, then undo when you retrieve. It would be a mess.
If you control all the computers that all your other computers talk to (and also their time sync sources), then smearing works great. You're effectively investing your own standard to make Unix time monatomic.
If, however, your computers need to talk to someone else's computers and have some sort of consensus about what time it is, then the chances are your smearing policy won't match theirs, and you'll disagree on _what time it is_.
Sometimes these effects are harmless. Sometimes they're unforseen. If mysterious, infrequent buggy behaviour is your kink, then go for it!
Computer clock speeds are not really that consistent, so “dead reckoning” style approaches don’t work.
NTP can only really sync to ~millisecond precision at best. I’m not aware of the state-of-the-art, but NTP errors and smearing errors in the worst case are probably quite similar. If you need more precise synchronisation, you need to implement it differently.
If you want 2 different computers to have the same time, you either have to solve it at a higher layer up by introducing an ordering to events (or equivalent) or use something like atomic clocks.
Google explicitly built spanner (?) around the idea that you can get distributed consistency and availability iff you control All The Clocks.
Smearing is fine, as long as it's interaction with other systems is thought about (and tested!). Nobody wants a surprise (yet actually inevitable) outage at midnight on New year's day.