Its a trade: Does it pay?

During a lifetime no insurances of any  kind pays back.

My best advice is to save the money and put them in the bank.
Then when accidents happen, and they will, you just eat the expense.
I have been insured for everything all my life. And since I have never used the insurance much, I have a huge deficit on that account.
And for what? Feeling safe? being secure? There is no such thing. And assets are maybe not assets but the opposite. Whenever you your are stuck with a thing you are stuck in the past.

Maybe it is good when everything goes up in flames or gets stolen, so you can renew yourself.

For those who doubt my words, take a look in your garage or your garden shed and see those prized possessions you insured for a high cost some years ago. Or take a look on your shelf and see the old camera gear that is useless nowadays.

Tools are useless without human hands on them.
The only asset worth while is you, your intellect and your health. That will last and that is valuable, -so insurance that.

Isn't there a difference in premiums if you do this for a living (professional) versus just owning equipment as a hobbyist?

There is for me.  I just called my home insurance again and they said - yes it would be cheaper if you could insure your camera within your home policy.. but I can't do that - sorry.  If you are using your camera for a business it needs to go in your business insurance... because of the risk and how much it is used.  The thing is - I probably use my camera a lot less than a lot of hobbyists.    So far my best solution to get the cost down has been to simply insure less of my equipment.  I cut out the insurance on things that a burglar wouldn't steal if they were going through out house (like large lights and stands etc).

Its a trade: Does it pay?

During a lifetime no insurances of any  kind pays back.

?? eh?
a few years ago my dumbo husband put petrol in our diesel X5. We had the whole thing fixed under insurance.  (apparently this is quite common and BMW now have a policy that if you're that dumb you have to pay for the repairs yourself)

in 2010 my Mini had an attempted break in; (I actually had all my gear (and a friends') in the boot and rear seat.) I had a gorgeous soft top Mini Cooper and they cut through the fabric, only to discover they couldn't reach their hands through due to the roof brace thingys. So I was left with a 4in gash. The entire roof bit had to be replaced, as well as the windows which had to be matched to the new roof. Can you imagine how much that cost?! I only had the car for two years, so the approx $2k in insurance was certainly worth it!

But Im a crazy DIY guy, from far out in he country where we use pigs for pets and ploughs.

Trained pigs pulling ploughs has to be your ultimate niche.   
Problem might be creating a market for the images.

FYI

http://photo.net/learn/insurance

When I started in microstock (2005), although I treated it like a business as far as using our Tax guy (reporting earnings, deductions, etc., alongside my 'real' job), I never got around to thoroughly investigating 'business' insurance and left my equipment on the 'house' insurance.  A year ago, we experienced a HUGE home break-in, and ~ $17K worth on lenses were stolen.  Amazingly, the thieves left my 5 plus Nikon camera bodies. 

Amazingly, our insurance company replaced ALL the lenses and flashes that were stolen, but did say I had to from now on carry a business rider since I was using it for business purposes as well as pleasure.  One of the lenses was the Sigmonster (Sigma 300-800mm) which I had purchased for ~ 2200 around 2006 or 2007, it was a steal of a price even then...

But the 'replacement' cost is now ~8,000 so I received the newest iteration with lens coatings my 'old' model didn't have, because my old model isn't sold anymore.  Insurance is for the unexpected, not the expected.  Perhaps you might consider just insuring what you would really want replaced and perhaps could not afford to otherwise replace.  Also maybe see if there are higher deductibles that might lower premiums, like some do for health insurance...