Update:
Finally, I saw some Light and understood why is working the (Tilemap.TileToPositionX(loopindex("Y")))
It's because your Map it's perfectly aligned on the Grid and the Origin Point of the TileMap (0,0) also the Tiles are symmetric 64x64
So even that the true it Loops Retrieving the X-Coordinates Of the Tiles using the Index of Loopindex("Y") but because the Tiles are symmetric and Both Indexes start at 32
Example:
(Tilemap.TileToPositionX(loopindex("Y=0"))) >>>>> 32px at the X Cordinates
(Tilemap.TileToPositionX(loopindex("Y=1"))) >>>>> 96px at the X Cordinates
(Tilemap.TileToPositionX(loopindex("Y=2"))) >>>>> 160px at the X Cordinates
(Tilemap.TileToPositionX(loopindex("Y=3"))) >>>>> 224px at the X Cordinates
Etc.....
Will be the same as if you used TileToPositionY
(Tilemap.TileToPositionY(loopindex("Y=0"))) >>>>> 32px at the Y Cordinates
(Tilemap.TileToPositionY(loopindex("Y=1"))) >>>>> 96px at the Y Cordinates
(Tilemap.TileToPositionY(loopindex("Y=2"))) >>>>> 160px at the Y Cordinates
(Tilemap.TileToPositionY(loopindex("Y=3"))) >>>>> 224px at the Y Cordinates
Etc...
This Time you been Lucky as the TileMap was aligned to the Grid :)
But if the TileMap wasn't Aligned to the Grid Example:
TileMap Position at (250, 92)
and the First Tile Coordinates will be at (X=282, Y=124)
So if you use the same System as you did to Retrieve the Y-Coordinates
(Tilemap.TileToPositionX(loopindex("Y=0"))) >>>>> 282 px at the X Cordinates (Wrong)
Vs
(Tilemap.TileToPositionY(loopindex("Y=0"))) >>>>> 124 px at the Y Cordinates (Correct)
as you can see the Results can be very very wrong, Conclusion the sooner you start using the correct expressions the fewer mistakes and headache you will have in the future, even if it did work this Time swapping the Loopindexs is not guarantee it will work next Time, but if you use always the correct Expressions you will have peace