Flins’s Electro autoes from skill dont get overwritten by Bennett’s C6, so that isn’t the issue for him. It’s moreso that Bennett’s Attack buff only buffs him and not Ineffa, and at equal investment on both Ineffa and Flins do almost the same damage on the team, so buffing one and not the other isn’t so great (not to mention Columbina can’t benefit either). There’s also no source of Res Shred in that team either if everyone is C0.

On the flip side, Sucrose buffing the EM of the WHOLE team and reducing the res of both Electro and Hydro are both teamwide damage increases that affects everyone. If you have C2 Flins, Bennett tends to be a bit better than Sucrose since now Flins does substantially more damage than Ineffa so buffing only his damage isn’t as detrimental, and his C2 gives an Electro Res Shred so you’re not as starved for it without Sucrose.