Graves should not be overly decorated or embellished or built up.

However, if the bar is erected to prevent people from trespassing or desecrating the grave, it is fine as long as it is simple; for we ought to spend our valuable resources to greater priorities.

Think of the many millions all over the world (including the Muslims of Rohingya) who suffer the worst forms of deprivation.

The money wasted on embellishing graves and planting flowers on the graves can be given in charity to them which would benefit the dead far more than any such material things.