stylistic ligatures are meant to improve both code readability, and code writing.
These are, I think, primary goals of ligatures for monospaced code aware fonts like this one.
The cosmetic aspect is of last resort (and always subjective).

According to these principles, this issue is not at all about wether a ligature is beautiful or not.

When a ligature changes the perceived order of symbols, it goes against code writing.
When a ligature make it not clear what symbol is used, it goes against code readability, and code writing.

Below are some examples as such ligatures that could be reworked to improve either code readability, code writing or both:

• !==
  The current result seems to indicate that the input is =/=
  There are 2 drawbacks:
  • symbol confusion:
    it seems the input is using a / instead of a !
  • order confusion:
    when you select the first character of the ligature,
    your selection appears to be a = character while it is in fact a !
• != same problem as !==

Note: this issue is extracted from #11