The problem with running Workbench in interlaced mode is that it just gave you tiny text and icons: the ROM only had a single bitmap font in 8 and 9 pixel heig

The problem with running Workbench in interlaced mode is that it just gave you tiny text and icons: the ROM only had a single bitmap font in 8 and 9 pixel height size, and adding custom fonts to your boot disk would've taken up a whole lot of space. (Similar to running unscaled High-DPI today on systems that weren't designed for it out of the box.)