>>38335277>Lava PlumeGood move, but has fairly bad distribution and is resisted by Fire-types, which are immune to burn. The combination of low-ish power and the frailty inherent to many Fire-types doesn't help it. Mons like Heatran, Torkoal, Camerupt, and Flareon still find it useful, but it's just not as strong or common as Scald.
>DischargeAnother decent move, but doesn't mesh well with the frailty of many Electric-types. Think of your average fast-but-frail special attacking Volt Switch user--do they really want to spend a lot of time fishing for paralysis? Remember that paralysis, while very good, doesn't deal damage. Something like Keldeo could abuse Scald to weaken its checks, but Electrics can't really use Discharge the same way. Further, you can switch both Ground- and Electric-types into Discharge to eat the attack and avoid paralysis, whereas Scald hits the only burn immunity super effectively. Discharge is still good on mons like Zapdos, but it's not nearly Scald-caliber.