BJJ techniques: basics or fancy stuff?

He he.

Fancy moves, can't live with them can't live without them

How much should you invest in them depends on your current level. For example: If you don't have your armbar down and to the point where you can hit it with high percentage, it is pointless start learning its fancy cousin flying arm bar.

Reason is obvious: what is the point of getting that first part of sucking guy into it right, if you don't know how to secure it, lock it and finish it on the end (and he just shakes you off). When you are pass that point and yo are confident about end part, by all means do it at least to the point that you can recognize it when somebody is setting it up on you.

You can also think of it this way. If you pay close attention, those fancy moves are attempted a lot on white belts matches, less on the blue belt, rarely on purple and as it goes, I doubt you'll ever see it in black belt match. Even in No GI and mma only time somebody gets it, was against somebody that is primarily striker that had no training in grappling and jiu-jitsu, or by total surprise in first 3 seconds of the match.

Reason for this is very simple. Fancy exotic moves relay on multiple steps and often surprise, more steps there is more mistakes you can make and more time opponent has to detect danger and defense against it.

So bottom line: Do they work?

If you don't know how to defend and they get you by surprise or off balance, sure they do! So learn about them, have somebody do them to you in the gym (watching videos will not help you much - without mat time).

And try to come up with something more usable in tournament then this

Remember:

Always make sure you got simple version of the move down, before getting into more complicated variations.

Come up with strategy about how to defend them before you move on, cus you truly learn the move only if you know both attack and defense to the move.

Hope that helps.