I cannot think of any overwhelming reasons to not buy from Amazon. The prices can be good, shipping is up to you, and they are pretty good with returns of defective products.
About the only thought I have is the lack of a local retail outlet that you could return (convenience and speed).
As far as manufacturer taking care of you - it depends on the manufacturer, but you should generally receive the same treatment regardless of where you buy it (other than “gray market goods - a whole different story).
Some credit card issuers have automatic warranty extensions built in (been so long since I even had a credit card, I don’t remember which ones).
And as far as extended warranties - they are generally a waste of money, particularly in your case - as they normally don’t cover abuse (children tearing it up). Some can be a bit forgiving, but most will deny the claim if it was dropped, had parts twisted off, etc... IN fact, any signs of abuse can often result in canceled warranty...
Thanks for saying that about extended warranties. I’ve felt they were ripoffs for years myself.
I have an old Canon Powershot, about 4 years old, and it went kablooey on me in the middle of a sporting event trip to Hawaii last year. The kindly Hawaiian photo shop owner told me that the specific product has been flagged for free repairs for that specific problem, and to send it in to Canon when I got home.
My own camera shop here on the mainland denied it. They would fix it for $$ too beaucoup, so I was going to dump the camera. I called Canon though to be sure, and the Hawaiian guy was right - they had me send it in for FREE, their packaging, they repaired it for free, and the dam* thing is still kicking today! (Free plug for Canon)