>>55236756h typhlosion's niche over blacephalon is doing sun eruption things, it doesn't have the competition with solar power charizard with weather ball like the original because it has a really good secondary STAB and its higher special attack means it actually outdamages zard's weather ball, which is significantly lower risk to use, by a notable margin
252 SpA Choice Specs Typhlosion Eruption (150 BP) vs. 168 HP / 0 SpD Abomasnow in Sun: 2232-2628 (614.8 - 723.9%) -- guaranteed OHKO
252 SpA Choice Specs Solar Power Charizard Weather Ball (100 BP Fire) vs. 168 HP / 0 SpD Abomasnow in Sun: 2232-2628 (614.8 - 723.9%) -- guaranteed OHKO
252 SpA Choice Specs Typhlosion-Hisui Eruption (150 BP) vs. 168 HP / 0 SpD Abomasnow in Sun: 2368-2788 (652.3 - 768%) -- guaranteed OHKO
Obviously you're not going to be fighting abomasnows often, but it's a good punching bag for numbers and also the first thing on the calc. It seems like a pretty intentional balancing of Eruption, if nothing else. Dropping 5 speed rarely matters, and Hisuian Typhlosion commonly sees use with a scarf set anyway, and it's doing pretty solid on niche sun teams and in RU.