Just for the record, pre-AP cars only do hill-hold for a few seconds (this was an OTA upgrade, not an original design feature; they are apparently using the link to the braking system provided for traction control). However, AP cars have (effectively) direct control of the footbrake needed for self-driving functions and so hill-hold is now just part of that and unlimited in duration.
In practice, the difference is really only one of convenience: with the pre-AP car you keep your foot on the footbrake and the hill-hold covers you for the period while your foot is in transition from footbrake to accelerator; with newer cars you can take your foot off and wave it around (though personally I probably wouldn't).
You can, though it's much harder to do than just relying in the hill hold.
The accelerator pedal doesn't in effect act as a brake at the sort of speeds we are talking about here. Regen is ineffective below about 5mph.
If you were coming from a manual handbrake, then I'd say there's a moderate learning curve; converting from another implementation of hill-hold should be easy.
My first experience of no handbrake/hill-hold was a complete nightmare - on a rented Renault in Portugal, where nobody told me you were meant to just drive away with the handbrake "on", and the car's base model engine only barely had enough power to start away on a hill in the first place (with 7 people on board). And then my brother (who was supposed to be driving but had forgotten his licence!) navigated us across a "short cut" of super steep hills where you had to stop to let past anybody coming the other way...
Having been scarred by the memories of that trip (and spending intervening years driving manual with ordinary handbrake), I was somewhat concerned about the lack of handbrake on the Tesla. In practice, it was easy to get used to - the almost unlimited power of the Tesla makes it a world away from that poxy Renault.
