Does Wallop's consuming a buff count toward Sett Brawler's ability for +4 attack?

Ruling: Spending a buff on Wallop's additional cost does not trigger Sett Brawler's +4 attack ability. Spending a buff is the cost of activating Sett's ability, so the buff must be spent specifically to activate Sett's ability to gain the +4.

Nuances:

• Sett's ability is not passive and does not have the react tag, so it cannot be used in response to other effects like Showstopper
• When using Showstopper on Sett, you must move to battlefield with +4 and a buff because there is no timing window to use Sett's ability while Showstopper is resolving
• You can spend a buff from any unit to activate Wallop, allowing you to use Sett's ability for +4, then play Wallop using another unit's buff to ready Sett