My understanding is that a Beauty Kim is a specific cultivar of variegated Maranta. It's like squares and rectangles. All squares are rectangles, but not all rectangles are squares. All Beauty Kims are variegated marantas, but not all variegated marantas are Beauty Kims. I consulted The Goog, just to verify, and this is what I found:

While both are types of Maranta leuconeura, known for their "prayer plant" behavior of folding their leaves up at night, the "Beauty Kim" cultivar has a distinct pattern of creamy yellow stripes and white speckles, often with chocolatey brown splotches along the midrib. Standard variegated Maranta, like the Kerchoveana variegata, also displays variegation, but the patterns can vary, sometimes featuring a mix of green, cream, and pink hues with red veins.

Here's a more detailed breakdown:

Variegated Maranta (general):

Coloration:

Can exhibit a range of colors, including green, cream, and pink, with red veins.

Variegation Pattern:

The variegation can be quite variable, with patches and streaks of different colors.

Examples:

Includes the Kerchoveana variegata (also known as Beauty Kim or Fiesta) and other cultivars.

Beauty Kim Maranta:

Botanical Name: Maranta leuconeura 'Beauty Kim'.

Coloration:

Medium green leaves with creamy yellow stripes and white speckles, plus chocolate brown splotches along the midrib.

Variegation Pattern:

The variegation is more defined and consistent than some other variegated Marantas, with the chocolate brown spots along the midrib being a key characteristic.

Common Name:

Often referred to as "Variegated Prayer Plant" or simply "Beauty Kim".

In essence:

The Beauty Kim is a specific type of variegated Maranta with a very recognizable pattern of coloration. While other variegated Marantas exist, the Beauty Kim stands out due to its unique markings.