Is it needed? No.
Will it happen? Most likely.
Is there a story reason for it? Yep, assuming we 'sacrifice' the power of our artifact weps to end the big bad in Argus (sap ourselves of strength, then squish).
Numbers are numbers, and the size of them are largely irrelevant so long as the percentages are still roughly the same.
If you have 10mil HP or 100k HP, it makes no difference as long as the boss hits for 5% HP (500k/5k respectively).
The only difference is aesthetic.
Some people may struggle with interpreting larger numbers quickly, so the smaller they are, the more digestible they are.
Having 100k HP and taking a 5k hit can be easier to read than 10mil HP taking 500k hits.
Also, secondaries are easier to understand when they are maybe in 100s instead of 1000s.
Either way, though, it all comes down to %.