NX-OS Upgrade Non-ISSU

What is the difference between install-all vs manually defining kickstart and boot variables? On Cisco's guidelines:

I can either do

Method 1:

install all kickstart n7000-s1-kickstart.7.2.0.D1.1.bin system n7000-s1-dk9.7.2.0.D1.1.bin

which will automatically reload the switch with the updated code

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or I can do

Method 2:

boot kickstart bootflash:n7000-s1-kickstart.7.2.0.D1.1.bin

boot system bootflash:n7000-s1-dk9.7.2.0.D1.1.bin

copy running-config startup-config vdc-all

reload