An image showing a 64 by 32 isometric ground tile. It shows a block with height = 0.5 times width (32 pixels) and one with 0.612 times with (39 pixels) and that the former lines up too perfectly with the ground grid and looks confusing, while the other one doesn't and so aids depth perception
https://s3.wasabisys.com/pmg-media/media_attachments/files/111/521/346/785/428/056/original/8758576b52d92784.png