It only makes sense to use any attack strategically. That's what strategy is. Using attacks sensibly. And strategy does not mean 'surprise attack'.
Mako's no-motion, 1 second charge means he has the ability to use it strategically in far more ways than Azula did. Ozai managed to use it against Aang and against Zuko when Zuko had him on the ropes with his swords and Azula used it against Zuko in their very first fight at the beginning of Season 2. Those weren't surprise attacks, since his opponents were aware of him, and it was't a bad shot either. Both of them would have been dead if they hadn't known lightning redirect. Azula also would have killed Zuko in the middle of their fight where, again, Zuko was aware of Azula, if Iroh hadn't stepped in and redirected it. The goon is a different story since, with Amon that close, it doesn't matter whether he had fire or lightning or water or earth bended. Once Amon gets that close, it's over, so using lightning in that instance was not wrong, it was just futile.
So, no, you're wrong that lightning can only be used as a surprise attack. Your kind of strawmanning here a bit. Just because a lightning bending failed once or can fail in some situations, that means it's a super risky technique mako would be an idiot to use, even though other people have used a far more complicated version of it in similar sitautions to good effect?
No. There is no other way of looking at this except how it is: Despite the fact that Mako's lightning is far more practical than TLA's lightning bending, he doesn't use it as much. Either A. The situations are somehow far more drastic that it is more dangerous for him to use lightning bending despite it's new convienence or B. He's just a far less effective fighter.