Are there skill limitations with playing with keyboard?

[Skyfire]

For most Tetris games, like Tetris Battle or Tetris Friends, the keyboard is often used (at least that's what I believe) compared to other controllers. However, with arcade versions of Tetris, such as the TGM series, it's recommended to use arcade controllers instead. This is obvious, considering that the TGM series is specifically for arcade. However, I've been wondering about limitations with keyboard, and it made me wonder if there's any real significance difference in difficulty with the joystick and the keyboard. I've been practicing TGM3 and am at Grade 3 right now (Classic).

So, here are my questions:
How much harder is it (generally) to reach GM with keyboard compared to arcade (if someone were to put in the effort)?

Is using keyboard a somewhat optimal way to rank up?

Since moving the joystick (from what I've seen from videos, not from experience, so this may be incorrect) requires more movement than just pressing down a key on the keyboard, what makes the joystick "better"?

"Joystick ---> Keyboard" Bindings (Idk if you'll need them but it may help)
Up: Space Bar
Left, Down, Right: Left, Down, and Right Arrow Keys
Button 1 (Rotate Left): Z
Button 2 (Rotate Right): X
Button 3 (Rotate Left): (I completely ignore that, but it's set to F)
Button 4 (Hold): C

I'm genuinely curious on this topic, so if you have any opinions/answers for my questions, then go right ahead!

[Jaymod]

1. It is logical that the keyboard requires less finger-movement to perform the same actions (the movement "joystick" is used to drop; Each finger is assigned to single buttons individually on the keyboard.).

2. From a technical perspective a controller should be better, BECAUSE: Input Lag. The controller doesn't send that much data compared to the keyboard (is notepad on, function-button pressed?, is caps-lock on? and the keyboard is used by other applications too, also your OS checks your keyboard for pressed shortcuts etc. pp.)

= the controller doesn't send any useless data and its not used by any other application (=the cpu doesn't need to calculate inputs for other applications).

So the joystick MUST be faster... the joystick isn't created to set all fingers on it (super smash bros players do  ); the result is that keyboard beats joystick because I don't think that the diffrence of the input-lag is noticeable to any human

[caffeine]

2. From a technical perspective a controller should be better, BECAUSE: Input Lag. The controller doesn't send that much data compared to the keyboard (is notepad on, function-button pressed?, is caps-lock on? and the keyboard is used by other applications too, also your OS checks your keyboard for pressed shortcuts etc. pp.)

= the controller doesn't send any useless data and its not used by any other application (=the cpu doesn't need to calculate inputs for other applications).

Correct me if I'm wrong, but "gamer grade" keyboards these days allow for polling rates of 1000hz (and higher).

Anyway, TGM was designed around an arcade stick. Just like other arcade games, at the highest level of play, you tend to see competitors using arcade sticks.