What is Vinyl plank or LVP? 

Vinyl plank is a composition consists of multiple layers, including a wear layer for protection, a design layer of printed and textured for the desired look, and a core layer for stability and water resistance. Vinyl plank is installed as floating floor like laminate with a click system to tie them together as one piece. SPC (Stone Plastic Composite) or WPC (Wood Plastic Composite)

Are they safe indoor?

Waterproof or water resistance:
LVP or Vinyl Plank is known for its water resistance or some say waterproof, (waterproof from the top meaning if water spills accidently on the top, you just wipe, and it will not damage the floor, but it is moisture resistant from the bottom to a degree. Vinyl plank flooring is suitable for areas like kitchens and bathrooms, where moisture is a concern. Vinyl planks are durable in nature and makes them resistant to scratches, stains, and dents, offering a long-lasting flooring solution. Vinyl planks come in variety of styles and colors.

Cost, Maintenance and Durability?

Cost:
Very affordable. Vinyl flooring is generally affordable compared to real hardwood or stone, making it a budget-friendly choice. 

Maintenance:
Super easy, requiring only regular sweeping or mopping to keep it looking its best.