Why are alkaline batteries (AAA or AA) made to be 1.5V while rechargeables are 1.2V?

In practice, alkaline batteries and rechargeable batteries can be used interchangeably in sets. They have only different voltage characteristics.

AA AAA Rechargeable Alkaline Batteries 3000mAh 1.5V / Battery Smart Charger Lot – Suncoast Golf Center & Academy

Duracell Rechargeable AAA NiMH Battery (4-Pack) 004133366160 - The Home Depot

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12pcs AAA Battery NI-ZN 900mWh 1.6V AAA NiZn Rechargeable Batteries PKCELL

[ 4 Packs High Power 1100mWh Capacity ] Pownergy Rechargeable Lithium AAA batteries 4 Packs,each with 1100mWh and Constand output with 1.5V, Direct

Rechargeable Lithium AAA Batteries 4Packs, 1100 mWh Rechargeable AAA Battery Constant Output 1.5V Li-ion AAA Battery, 2H Fast Charge with USB Cable

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recharge alkaline batteries, Alkaline Batteries

MDHAND 16Pcs 1.5V AA rechargeable battery alkaline battery Suitable for razor, LED lighting, wireless microphone, cordless phone, etc.

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» Are all alkaline battery brands the same?

Regular AA & AAA batteries are rated 1.5V and rechargeable ones are rated 1.2V why the dif and does it make a dif to the devices using them? - Quora

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AA AAA Rechargeable Alkaline Batteries 3000mAh 1.5V / Battery Smart Charger Lot – Suncoast Golf Center & Academy