How come DataGridTemplateColumn Visibility Hidden doesn't allocate space for the column?

How come DataGridTemplateColumn Visibility Hidden doesn't allocate space
for the column?

References

Reference NO 1

http://stackoverflow.com/questions/13586215/how-come-datagridtemplatecolumn-visibility-hidden-doesnt-allocate-space-for-the

Reference NO 2

http://stackoverflow.com/questions/tagged/datagridtemplatecolumn

Reference NO 3

http://www.pressingquestion.com/1350410/Wpf-Datagridtemplatecolumn-Visibility-Binding-Under-Mvvm

Reference NO 4

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Reference NO 5

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Reference NO 6

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Reference NO 7

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Reference NO 8

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