I never really thought I would use a tablet either
I think, in my case, the tablet had to be able to replace a laptop in most cases.
Not for work purposes, I don't travel and work usually. Not for 'real' things like document creation or major edits perhaps. Not for watching stuff on a connected TV.
So, I keep my laptop powered and cable-connected to a TV almost always.
But, when I want to browse Argos at the lunch table, tablet. Likewise conservatory, bedroom, garden dining room.
When someone, like offspring or a guest wants a better browser than their phone offers, tablet. No need to share a WiFi key either.
When I want to buy something from Amazon which requires more than trivial searching/analysis, tablet.
When I want to created shared lists, select a group of pictures to share etc., tablet.
When I want to travel so I have the ability to watch stuff, use Skype, edit docs, create if required, apply for jobs, return email with attachments, links etc., view PDFs well, watch stuff on the plane, tablet. Useful with the Easyjet luggage limitations.
For my purposes, a tablet is only useful if it is a laptop replacement and thus has to have a passable keyboard, has to be quickly accessible - not stuffed in some bag or folding case making it even thicker, has to be portable and reasonably powerful. Has to be small enough to be more portable than a small laptop.
Even if I could warrant the money for a Surface 3, it would be wasted because the main laptop hardly ever moves, maybe a docking station would fix that but then it is probably larger than I need/want and definitely more powerful as well as super expensive.
A trip last year had someone on it with an iPad mini and a separate Bluetooth mini-keyboard. Charging, at extortionate cost, was regularly required. The total combination was as thick as a small novel, it required a case to hold/protect both and probably cost a considerable sum.
My laptop can be a cheaper, non-ultrabook and my tablet can be less capable (read much cheaper) than a Surface 3 or fancy Lenovo laptop.
So, venerable laptop still running Win7 plus Surface 2 RT.
Docs appear on both (and the phone) anyway so they are always available.
Netflix on all, I can pop a TV show etc. on OneDrive as required by me or anyone else.
And, the Surface will run for a week with reasonable use.
Tablets can be useful, just get the right one.