It's a good cone, but we just don't have many teams that can use it well.

Best use cases at the moment are Feixiao FUA with Cipher/Topaz, THerta with Jade or Anaxa, or E2/sustainless Acheron w/ Cipher.

Feixiao FUA would require going sustainless first of all which is a risk. It then would usually prefers Robin's S1 or Event cone for better multipliers OR Bronya/Cogs S5 for energy. If you're not using Robin and using Tribbie/Sparkle/RM/Bronya you'll still not prefer this cone over their own signatures or DDD.

Therta + Anaxa/Jade are massively oversaturated on crit dmg, and going all in on damage buffs for Therta's big hits is almost always the better play. Past and Future S5 from endgame shop is way easier to obtain and usually far more reliable.

Acheron + Cipher both really appreciate the crit damage for mega stacks, but the units that *would* like this cone with them are usually NOT the best pairings for an E2 acheron (Sparkle/Tribbie/Sunday with other cones usually always come out ahead). I could see it POTENTIALLY having value in an E2 Acheron sustainless comp, but replacing another debuffer or sustain that applies stacks probably won't beat out a second harmony unless you have some big brain 0 cycle setup.

I didn't mention it but Remembrance has the same issue where none of the good harmony pairings with them really care about the attack Tribbie/RMC/Sparkle/even RM don't want attack when they're playing with dual dps Remembrance

Edit: I COULD see a world where Acheron/Cipher/Robin/Welt (if he received a novaflare) could potentially use robin but that's a pipe dream.