PBP is a high level language where as ASM is a low level one. And, I think the biggest disadvantage of having support for graphics displays is going to be the bloated output. Better to write your own routines because there may be certain functions that you don't require which will only cost you code space. One of PBP's strong points is that it compiles to a highly optimized small output, most others don't. If PBP did have support for graphics displays - you have to remember that the entire library would need to be included in your code, even if you use all, some or none of its functions. Not worth it.
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