ISIS Loopback configuration

[robert.x.bergeon.-nd]

For a Level-2 only IS-IS network (multi-topology IPv4 and IPv6)

What is the difference between using passive-interface for the loopbacks, or assigning the isis process to the loopbacks

example for ios

router isis AREATAG
  passive-interface loopback 0

interface loopback 0
  isis metric 1 level-2
  isis ipv6 metric 1 level-2

versus

interface loopback 0
  ip router isis AREATAG
  isis metric 1 level-2
  ipv6 router isis AREATAG
  isis ipv6 metric 1 level-2

Can I assume these are equivalent?  Loopbacks would not create adjacencies in any case.

For a network with Level1 areas would these be different?
Are there relative best practices?

Thanks

[balaji.bandi]

when you configure passive interface, the interface configure will be removed and no hellos will be sent out.

[robert.x.bergeon.-nd]

>From my understanding - hellos are not sent from loopbacks in any case