Here's a few tips on why to not bother with complimentary ISP service addons.

Email for a start -- ISPs come and go. Sure you have some mainstays from the incumbent era like Optus or Telstra.

VoIP xfers could take a week plus from my understanding.

The key services to not take up from your ISP:

1. Email - no point because when you leave chances it will too. Or you may need to pay a premium to keep it ongoing. And if the ISP gets swallowed by another it may be well be gone or you may be forced onto their own domain.tld eventually. Gmail or Hotmail anyone?! Heck you could even add a custom domain name email there too for vanity or business reasons.
2. VoIP - not sure how it is currently in terms of days waiting for typical xfer of a voip churn from one isp to the other. But if you go to one of the industry trusted businesses like SipTalk or Crazytel, your VoIP will work immediately regardless of churn to a new ISP as it is independent. You dont need voip to be handled by your isp when you can shop around for ad-hoc plans that suit your needs. With this method though, unless your isp router allows third party SIP on their router, you'd need to buy a new dect phone with voip built into it. Same with desktop phone --  they aint expensive these days.
3. IPTV. Go retail boxes or independent source. Plenty to choose from here. Most have a online sub to choose from.

The most obvious bonus is that you're not shackled to one ISP. And can switch around with ease and make use of existing ISP bargains and such.