The clock animation was removed / reduced as a part of the last firmware update in order to reduce lag (especially on desktop wake-up).

I don't believe there's any way to 'undo' this. That said I'd much rather have less lag than some fairly pointless eye-candy

 

Ok I get what you mean.. in the vid @ 1.22ish you see the clock on the homescreen with a continuous movement as opposed to a 1 click notch movement. However if you select that clock on your phone right now..it will not be continuous as shown in the vid.
I get it lolll..
I would have thought that the one click notch movement would cause lag if any (not that I encounter any lag)

 

A "sweep" second hand actually means a centre mounted second hand (as opposed to one having its own small dial on the watch face). However the term is also commonly used to refer to a second hand which doesn't increment in full second steps. In 'real' (as opposed to computer generated) watches they actually do increment, just in much smaller steps, usually 1/5th or 1/4 of a second - the mechanical Citizen on my wrist does 1/4 seconds.

I'm not sure if there is an accepted term for the 'ticking' second hand - they are often referred to as quartz (because most quartz movements increment in full seconds). Nearly all mechanical movements have 'sweeping' second hands, although some high quality quartz movements do as well (so they can pretend to be mechanical).