Responding to this, Dr. Hatem  Al-Haj, Professor of Fiqh, said:

The establishment and maintenance of mosques is of the greatest acts of good someone may embark on or take part in. This is by frequenting the houses of Allah, and it is also by building and maintaining them. Allah says: “The mosques of Allah shall be maintained only by those who believe in Allah and the Last Day; perform Salah, and give Zakah and fear none but Allah. It is they who are on true guidance” [al-Tawbah 9:18]

Abu Dawood narrated from Ibn Abbas that the Messenger of Allah (blessings and peace be upon him) said: “I have not been commanded to build lofty mosques.” (al-Mu’jam al-Kabir)

When Omar (Allah be pleased with him) ordered the rebuilding of the masjid, he said: shield the people from rain, but beware of using red or yellow as to not distract the people.

Having said that, it is important to say that the three sacred masjids are to be honored (without extravagance) for that brings comfort and confidence to the hearts of the Muslims.

The shades are helpful to shield people from the scorching heat of the sun in Arabia. The marble also makes the ground cooler. These things are not for extravagance, but rather for comfort. If there were other manifestations of extravagance, they are not from the sunnah of the Prophet. We must also honor the ka’bah and the Muslims have always took special interest in its cover, but as Ibn Omar (Allah be pleased with him) said, the Muslim is more sacred than it before Allah. That statement of his is not an exaggeration, for in the Muslim’s heart is the tawheed of Allah and faith in Him. This doesn’t mean to neglect the ka’bah, but it certainly means that we should give precedence to the hungry and needy Muslims, particularly those who suffer from other forms of injustice such as the occupation of their lands or embargo…etc.