When I first started collecting miniatures, Games Workshop had two scales for their Warhammer 40,000 universe- there was their normal gaming scale (about 28mm) and their Epic scale for games like Space Marine and later Titan Legions.
The cool thing about the smaller scale was that the games could include the absolutely massive giant robots that stalked the battlefields of the 41st millennium. The only issue with this scale was that it was VERY small- too small for some of the details we would like to paint.
I’m not sure exactly what motivated it, but the introduction of the Adeptus Titanicus gave rise to a new scale- something in between. This scale is nice because the huge Warlord Titans are about the size of Imperial Knights, and there’s enough room to really add some cool detailing.
And in the setting, they really love to add murals to their giant robots.