In my very limited experience, I think that diving in the same spot over and over has many good things going for it... especially if you do what we do and do "training dives" to work on specific techniques.
We spend a lot of our time underwater doing this... both she and I are cyclists, and we are used to training 2-3 hours a day, 6 days a week... that's just normal operating procedure for us. So training on specific skills underwater is rather second nature, and I think in the end it will make us better divers and safer divers.
Back in the 1980's, I had the opportunity to spend a half an hour talking with Geddy Lee, the front man and bass player for the rock band Rush. Really nice guy. Most of the conversation was spent talking about baseball (he is a BIG TIME baseball fan) but I did impose on him enough to ask one question about music that he had likely been asked a billion times before.
I asked Geddy what it takes to make it in the big time as a bass player (which I aspired to be). He said that virtually anybody with moderate talent could be an excellent player, and what he advised anybody who wanted to become one to do was "lock yourself up in a closet for two years, spend every minute you can practicing and get all the technical stuff out of the way upfront". After that, how far you rise depends on hard work, talent and some luck. Songwriting, he said, was something you either can do... or can't... but actually playing is more about hard work and dedication...
That's kind of like what diving in the same spot can be if you are trying to become good at the CRAFT of SCUBA, I think (with my NOOB brain at least).
In my NOOB brain (again, I claim to know absolutely nothing, this is just what I THINK), diving in one or two familiar locations doesn't prepare you to dive in other situations (the only way to learn about things like surge and currents is to dive in them) but nailing down things like buoyancy, air consumption, trim, etc. can be easier to do if you can just "set aside" all the different conditions you find in new spots.
Having said that, diving ONLY in the same places can lead (again, my NOOB brain surmises) to developing the bad habit of expectations... things are just plain different in warm salt water than cold water with limited vis.
Me, I will do most of my dives in cold fresh water because that's where I live. One cold fresh quarry is pretty much like any other cold, fresh quarry when it comes to technique. But I also plan to do as much clear salt water diving as I can afford.