Well... let me add something with a little anecdote.
I used to play SSFIV with a fightstick for a month or so before my bro was like 'hey i'm selling my xbox k u wanna sell ur stuff 2 k then'. I was a little annoyed but not too big a deal. If I still wanna play it i'd probs do it on PC or something.
Well, I liked that game. On xbox live if you tried to button mash you would get stomped over. I took the time to learn all the moves of my favourite characters. That was why I bought a fight stick. It was lots of fun.
One day I managed to convince my brother to play a game against me. He is usually like 'no fighting games suck I wanna play halo,' but I managed to convince him because a friend was over and he was backing me up. He decided to do crouching fierce the entire match and I lost a round to him. I had to be a bit more careful to beat him. Button mashers, even nowdays are still dangerous if you are not good at the game. Still, superior strategy wins
Fast forward a year, when my nephews were over. I have street fighter 2 turbo on my wii virtual console, and decided to play it with them. I belive the youngest nephew I was playing with was... 5? (sorry not very good at remembering since I don't see them very often). The other newphew was not much older. They were both constantly beating me. There was the older one managing to get grabs all the time, and the younger one, also pulling off grabs and general button mashing. I could not beat them at first, until I played e.honda. What was my strategy to beating these extremely young button mashing masters of street fighter?
Sumo head butt
Jumping medium punch
Hundred hand slap.
All I did was head butt, and spam the same punch button the entire round to defeat him. I felt rather stupid. Maybe street fighter 2 turbo requires a lot of cheesy play to be successful at it? Maybe.
I decided to use these newly found skills I mastered on single player, and it worked very well.
TL;DR version. Beat my nephews who are over 10 years younger than me by head butting, jumping medium punch and hundred hand slapping. Press the same button over and over again. Basically, button mashing.
My opinion? Nah, fighting games aren't about button mashing really, if you lose to button mashing, you are just as bad as them, if not worse. If you think that you lost because they were button mashing, and if they 'played properly' you would have won, guess what that makes you? A scrub. A decent person who 'plays properly' would wipe the floor against you.
Although I will admit people probably think fighting games are about button mashing because it really works against inexperienced players.