Generally, a small handful of bad blocks (and they come in groups due to the physical format and sector size emulation) aren't an indicator of imminent trouble. If they can be written to properly, then that could just be random data corruption caused by e.g. an unlucky hard shutdown, vibration, or other random thing. If they can't be written to, it could just be very minor drive damage or a weak area of the platter (and in this case, the drive will remap them and increase the bad block count in the SMART data)
Now if you start getting into the hundreds, then yeah, the drive is dying.
Lots of drives don't seem to measure their own power supply... That means if you run them on a laptop with a slightly out of spec power supply, you can get the drive marking hundreds of bad sectors, yet when you put them in another machine they're fine again.
If you're designing something as complex as a drive, you would have thought they'd have a bit of electronics to test the power supply and refuse to work (with some relevant error code) if it's out of spec.
Now if you start getting into the hundreds, then yeah, the drive is dying.