Allo Isolator

Good morning,

i am new to the forum and using volumio about 4 weeks now.

I have a RPi 3b+ with allo piano 2.1 and allo reclocker.
The Pi has a normal cheap power supply and the reclocker is powered by an IFI ipower 5V (and powers the DAC).

My question is:
is there any benefit in adding the isolator?
Is it really necessary to use the battery pack?
That does not seem to be very handy to me.
Do I really need a third power supply?
Can’t the IFI do the job or do I not get any better in audio quality then?

(sorry for my bad englisch, it is not my native language).