Thank you for your answer! My site is new so I basically have no backlinks yet... Starting off only using .com would mean any new backlink on the web would also go to .com. This means I would have more backlinks if I only use .com. When using the regional domains, all of them would have less backlinks and so all of them wouldn't rank high. But I don't know how big the benefit of localisation is to search engines...

I own both the .com domain of my brand name as well as a regional domain for .ca .co.uk .ie .co.nz and .com.au. I'm unsure whether I should be using the .com domain (and redirect all others to it), or whether I should be using all of the domains without redirecting them to the .com domain. Using only the .com domain and redirecting the others to it, has the advantage of more backlinks going to the .com domain. These backlinks would be distributed over the regional domains if I used all of the regional domains instead of only the .com domain. This is a disadvantage of using regional domains. But using the regional domains has the advantage of a higher search rank in searches originating from a specific country...

My question is: which is more important/weighs more? The amount of backlinks or the localisation (Top Level Domain/TLD) of the domain?

There is also the issue of duplicated content, but I read that Google isn't so strict on that so that wouldn't be an issue?