At a competitive level, (U 2100 or above), these openings will be less common. Most openings are unknown or not played much since there are refutations. At the 1600 or 1700 level, it might catch players out of their prep. However, as players get better, they start to analyze lines that they may not encounter, but when they do, they will know how to play against, and probably beat it.
Catch your opponent off-guard with an unusual opening!

if you really want to avoid your terrifying opponents book then just reisgn on move 1.
Here topic of discussion is not to avoid an opponent. Rather it is- how to improve at chess play. I agree to your point that a3 move perhaps does not achieve much & that a seasoned player playing with black can equalise or even attain an edge. But at sub 1400 level when playing a 5 minutes game- it will surely surprise your opponent & may force them to play in a way that they would not if book moves were used for opening. Also, as I mentioned when opting for such plans deep analysis by Computer may be required to understand different variations so that one may play accurately. Plus, I have also stated in my annotation that it is not possible to prepare against all possible choice of move by your opponent- in that case you also be quick to think & improvise.
This shows your lack of understanding of the Wing Gambit more than anything really. In the Sicilian it deflects black's c-pawn from the centre so he can't attack White's centre. Playing it against 1...e5 is pointless and can easily be dealt with by Black.
You won because your opponent couldn't find the correct defense in a position where he is winning. The opening didn't affect the outcome at all, so why not play good openings and try to learn the purpose behind the moves, rather than mixing everything up?

Bareilly -- Fiveofswords talks the truth ! ie; you should not play unusual opening moves because you are intimidated by your opponent's opening book knowledge. Seems you play moves like 2 a3 to force your opponent to "think", and not play automatic Book moves. That I applaud you. When we force our opponent's to consider how properly to approach the position, the smarter player -- the one who knows how to evaluate a position -- should prevail at the Slower Time Controls. The faster the time limits, the more the coffeehouse player, the one looking for cheap tactics can prevail.
That said, here are my game comments.
2.....Bc5 developing the Bishop here is really askinig to be hit ! why ?
yes, 5 .....B xc3 is a very poor move. White is now better as he is several tempi ahead in an open position -- always a dangerous position to be in for the defender.
On move 7, I would opt for B - g5. As the game progresses, on move 11, Q -g3 looks stronger -- does not block your B. You would then be pressuring his King, threatening to push away his B with pawn to h3 and then your B threatens to take the pawn on h6 for free.
As it was, you apparently befuddled your opponent into taking great amounts of time to capture your gifts, until he finally got to the final position feeling very frustrated.
There is a great deal to be said about controlling the initiative of a game. However, when you play slower chess, you should look to sounder principles to govern your play ( my opinion ).
Yes, much more butchery happens in fast chess. Is that what you prefer playing ?
Dear All!
Chess is a serious game but we surely can have some fun with a prepared line- to deliver a quick defeat to our opponent.
I came across "Delayed Wing Gambit" against Sicilian. However, with some improvision it can also played against other openings against black.
While I am not recommending anyone to use this line but this post is just to share how we can come up with new ideas & with help from deap computer analysis play accuarately in a competitive setting.