Rupee: Winter ShopperLimited

Her performance is too low to use as a main Burst 1. She has reload speed and Burst 1 re-entry, but her taunt and lifesteal tier and the delay right after her Burst make her hard to see as a core slot in regular bosses or Arena.
Her role differs from the original Rupee (Burst 2 firepower type), and higher-tier Burst 1 units like Liter, Noah, and Noise come first.

Her last bullet applies the Winter Premium1 defense buff, and each time an ally uses a Burst Skill, she stacks VIP Gift2 Shopping. If Shopping is at max stacks when Full Burst ends, she raises Burst Gauge filling speed so the team fills Burst Gauge faster.

Shopaholic DateB taunts all enemies, grants healing proportional to attack damage, and raises ally reload speed, and since she Re-enters Burst stage 1, Burst 1 can be used again in the same cycle. As an Assault Rifle, her Burst Gauge contribution is average.

Keep sustained fire going until the last bullet lands to apply the Winter Premium1 defense buff.
In stretches with taunt and lifesteal active, time Shopaholic DateB manually.
Otherwise, you can leave sustained fire and reloads on auto.

There's almost no evidence of her being paired in main squads for recent Raids or Arena. Reload-focused theory lineups require heavy skill and Harmony Cube investment and are rare in the current meta.

Go in order: Resilience Cube for last-bullet triggers, Bastion Cube for sustained fire, and Vigor Cube for taunt survival.

Don't take DPS-oriented Elemental Advantage or ATK lines. For taunt and lifesteal survival, prioritize 4 Increased DEF lines, and fit spare lines, such as Hit Rate and ammo, to sustained fire.

If you don't plan to use her, leave her at 1/1/1. When raising her, focus on Shopaholic DateB's reload speed and VIP Gift2's effect that fills Burst Gauge.

She's only occasionally slotted for taunt and reload support in single-boss or practice stretches with no CP deficit. She isn't a main Burst 1 for Story, Raids, or Arena.

Winter Premium1 raises allies' DEF with every last bullet.
After VIP Gift2's Shopping reaches max stacks, she raises Burst Gauge filling speed so the team fills Burst Gauge faster.
Shopaholic DateB has high reload speed and lets her re-enter Burst 1.

While taunting, her HP drops fast when CP is lacking or in high-difficulty stretches.
There's a delay after her Burst until the next Burst 1, so her taunt and reload buff efficiency drops right after Full Burst.
She's outclassed by higher-tier taunt Burst 1 units like Noah and Noise.

The original Rupee is an Iron Code Burst 2 firepower type, while Winter Shopper is an Electric Code Burst 1 Defender, so they aren't replacements or comparison targets for each other.