If you want to print out things you weren't able to imagine, but other people were - then it's an argument for not getting a 3D printer but having it printed at a 3d-printing service; it will be cheaper, higher quality, less hassle, and more options for materials/techniques than a single printer can provide.
Somewhat. It depends on what you value. There are other considerations. If price is important to you, but time is not, it's cheaper to have a home desktop printer. 3D printing services are quite expensive. The size of the object also affects your decision. The larger the object, the more economic it is to print it yourself.
If price is less of a consideration, but time is more important, then you may find it's better to use a 3D printed service, so you don't have to maintain the machine. Or if you don't print very often. Or the object you want to print is relatively small, so it doesn't break your wallet.
The advantages you cite, such as higher quality and less hassle, will diminish, given the pace and directions for improvement of the current generation of 3D printers. I believe different materials and hence printing techniques, will remain a differentiator of online printing services for the foreseeable future.
