BASIC (old-school unstructured imperative) is structured as the "ASM" language for an old-school desk calculator from the 1960s, with a few tacked-on features around string manipulation, input handling etc. plus more, depending on the hardware. It was fine for what it was in the 1960s (a simplified "scripting"-focused version of FORTRAN), but the needs of even slightly more modern coding are very different, and BASIC would not serve them well.