I used to be a keen DJ, still do a gig once or twice a year, but my enthusiasm for it died about 4 years ago. So to break down your questions...
It was terrible as with in five minutes I was mixing like a pro, not because my skills has immediately come back after many years but because the decks did most of the job for me. Whilst still fun it felt almost no point as the skill and techniques were not needed. It told me what Bpm everything was, it could auto correct.
Beat matching is only a small part of being a DJ, and in my opinion the most mechanical and inconsequential part of it. It only lends itself to certain styles of music anyway and it's still possible to do a smooth segue between records that aren't the same tempo.
Much more important for a DJ is knowing what songs blend together well, judging from a crowd what songs to play, building your allotted set time to contain peaks and downtime, and for turntablists learning other skills like scratching. All of these are arguably things that can't be done by a computer so why not let technology take the tedious part of DJing that the majority of punters don't care about away?
Now I've noticed over last few years the professional DJs now use this too. Not really a talent worth high pound now eh? No wonder on line ups now I mostly see producers who I thought years ago were shit DJs, they no longer need to worry that they can't mix or scratch etc. I heard a track from TC the other day with a stupid voice over saying he won't play if you don't give him the cd decks stated in the contract. Pft.
As above the talent isn't just beat matching and never really was. Before the technology became available big names like Sasha, John Digweed, Carl Cox etc, were no better at beat matching than Johnny No-Name who played at his local pub every Saturday after DJing for 10+ years, but the reason they commanded a high fee was because the sets they put together were judged as worth more due to the quality of their music and in some cases their production history.
The whole Diva DJ demands are nothing new, and even pissants like me get stroppy when we arrive at a gig to find the venue has a mixer with no monitor, a mixer that looks like it was made in communist Eastern Europe and decks that should have been replaced 5 years ago.
Did make me want to go buy vinyl decks though, anyone on here still mix? Was a great but bloody expensive hobby. I guess a good thing for kids getting into it now it is crazy cheap after the initial output.
This cost was one of the factors that put me off DJing as a vinyl only luddite. Paying £6+ per song for stuff that mostly disposable took it's toll on me while I was at uni. If I had started a few years later when CDJs were becoming more popular I would probably still be doing it.
Even if you are a vinyl purist when it comes to DJing programmes like Serato are a great middle ground as you can play music from a laptop via decks and still beat match to your heart's content if you wish. It would certainly be a more attractive prospect for me to take my entire music collection to a gig, rather than hurting my back lugging a record bag with a maximum of 60 records to a gig. Alas I find the task of ripping the hundreds of records I own to a laptop too tedious a task to consider it.