There's limited research on readability of monospaced font. But this study suggests monospace is weakly more readable than variable-width font: https://dl.acm.

There's limited research on readability of monospaced font. But this study suggests monospace is weakly more readable than variable-width font: https://dl.acm.org/doi/epdf/10.1145/2897736 https://dl.acm.org/doi/epdf/10.1145/2897736