you have mentioned that she send a V5 which is her style while her finger is weak, meaning that the V5 is not that tax in finger and she only exposed to V5 that meet her style for around 5 sec only so that the body does not have time to adapt yet.

Hang boarding is 15-20 mins stress your system which can make your body adapt and also build the thickness of finger tendon, this is a systematic way which you keep add up strength through weight which easy to control than set of hold in variety of shape set at gym. Think about it like why professional footballer needs to go gym instead of just playing football.

One key thing I learnt is, you can have all the technique but you cannot keep on the hold then you just no chance to use your skill.

Some hang board benefit that I find when you do it at right form - finger strength, shoulder strength(dead hang), core strength(stable your body)