The reason this matters is that a lot of anti-spam software checks what IP addresses are authorized to send email for a domain.
(This only applies to the tracking code that your users install on their site, and nothing else).
By default this option is enabled for new white label accounts.
There is no extra charge for this, so we highly recommend using it.
This is because we cannot guarantee our IP will remain the same forever. Clicky is contstantly being updated with new features, and you'll definitely want to know about them.
If our IP does change and your white label breaks because you set it up as an A record, we cannot be held responsible for any outages. Whenever we release major new features, we always blog about it.