Quick take
Lumen Business Cash fits: Sole props and small teams with clear office or ads spend.
Summit Cash Rewards fits: Everyday spenders who want one card and zero math.
Fee and bonus math
Annual fee difference: USD 0 (same fee).
Welcome bonuses and spend hurdles are not apples-to-apples when one is cash and the other is points. Value points at a conservative 1 cent each unless you have a known redemption.
Approval path
Lumen Business Cash targets: excellent, good.
Summit Cash Rewards targets: excellent, good.
If either card uses a prequalify CTA, start there to avoid an unnecessary hard pull.