Auto thrust
It would be an almost certainty that the AT was NOT in speed mode, once below a certain height All protections are lost. Alpha floor on the bus lost below 100'. There have been accidents attributable to this.
I would think that the PDF was flying an attitude that would be normal for the approach, it was only at the last few hundred feet that he realised he was going to land short and raised the nose. However with no auto thrust active the speed rapidly decayed. No one appeared to have noticed the AT being out of speed mode.
Speed is not so often scanned as the AT usually takes care of it.
I would like to know at exactly what point the speed started to decay. There is so much thrust at idle on these engines and I would think it was not until the last few hundred feet when the speed decayed due to the AOA being increased to make the runway. At this point things become interesting and the pilots are wondering what is happening and why no thrust. This was the point to apply TOGA as no thought is required to push the levers to TOGA.
Thr Idle open descent on the bus would be the same thing. Which is why on a visual approach FD are off.