Button[ ] doesn't work?

Questions
,
1

(* This works *)

anima = False;
Button["Iniciar/Detener", If[anima, anima = False, anima = True]; 
 Print[anima]]

(* But this does not work *)

anima = False;
Button["Iniciar/Detener", If[anima, anima = False, anima = True]; 
 If[anima,
  ParametricPlot[{Cos[t], Sin[t]}, {t, 0, 2 Pi}]]]
2

Setting the Button as a Control in a Manipulate works

anima = False;
Manipulate[
 	If[anima, ParametricPlot[{Cos[t], Sin[t]}, {t, 0, 2 Pi}], ""],
 	Button["Iniciar/Detener", If[anima, anima = False, anima = True]],
 	AppearanceElements -> None
]
3

Thanks for your help.

4

A minor, cosmetic, improvement (FrameMargins → None):

anima = False;
Manipulate[
	If[anima, ParametricPlot[{Cos[t], Sin[t]}, {t, 0, 2 Pi}], ""],
	Button["Iniciar/Detener", If[anima, anima = False, anima = True]],
	AppearanceElements -> None, FrameMargins -> None
]