Subhanna Allah. Marco100, who is building and beautifying the masjid and with what money? And what are the circumstances of the masjid: in a poor area, rich neighborhood, someone's personal masjid, etc? I'm in Abu Dhabi and various shayakh of the Nahyan family finance masajid all over the city, putting their money to beautify them. These masajid are different from a masjid in a rural village in India. From the Shariah, the maintenance of the masjid was financed by the khilafah state which paid the groundskeepers and imma as well. In that sense, the state would NOT be focussed on expensive decorations when it had poor people to support, wars to wage, government officials to pay, etc. However, today, we are divided into nation states which include regimes that only focus on themselves and like in Qatar and UAE. So the matter should come down to the circumstances of the masjid. If its a local masjid in London or NYC, putting millions into decoration when Muslim schools and charities need funding would be very misguided. But Allah knows best.