Why button check?

(Competitive) (Ultimate) Marvel vs. Capcom 3 matches typically start with a button check. Do the players perform actions simply to check that (all of) their button assignments are correct? Is it not sufficient to see what the button assignments are?
My question comes from more of a Super Smash Brothers fighting-game knowledge background, where button assignments are typically non-customizable, so there are no button checks. And even in those SSB games whose controls are customizable, one need not button check them/perform actions to know that they are correct.
Best Answer
Regardless of where the button mappings occur in the gae, at any tournament, there's going to be a number of people using all sorts of controllers, sticks, pads, hitboxes, etc.
Having a button mapped incorrectly doesn't count as a hardware malfunction in standard (Evo) tournament rules; if the button is mapped to an incorrect action, then that's on the player.
Given those two things, because you never know who was on the console before you and with what kind of custom controller/mappings, players go through button checks to make sure that all of the buttons on their controller map to the actions that they expect.
Granted, most sticks/pads nowadays map to the default mappings in most games (especially Capcom ones), and chances are that the player before you on the console had the "standard" mappings.
Of course, it's better to be safe than sorry.
Also, there are a number of people who turn off the KKK and PPP mappings, as hitting one of these means that you'll get a HK/HP (because of input priority) while some people want them turned on.
Pad players also tend to have very specific custom mappings, depending on their character and what buttons are more comfortable to them.
Pictures about "Why button check?"



How do you check whether a button is not clicked?
\u201cjs see if button was not clicked\u201d Code AnswerHow can I tell if a radio button is checked?
To find the selected radio button, you follow these steps:How do you check if an element is not clicked in Javascript?
\u201cjavascript if not click on element\u201d Code Answer'sHow do you check if a button is selected Javascript?
Use document. getElementById('id'). checked method to check whether the element with selected id is check or not. If it is checked then display its corresponding result otherwise check the next statement.Sonic Fox UPSET and DQ's in DBFZ World Finale | DNF Duel Hype Action | FGC Reacts!
More answers regarding why button check?
Answer 2
It's due to players having completely different ways of binding actions to buttons; think PC players.
For example, for Street Fighter, some players may want to bind their light, medium, and heavy punches to different buttons, and their kicks to different buttons, so using a button check is a great way to make sure the player's preference is correct and avoids issues mid-game.
Sources: Stack Exchange - This article follows the attribution requirements of Stack Exchange and is licensed under CC BY-SA 3.0.
Images: Klaus Nielsen, Anete Lusina, Klaus Nielsen, Julia Larson