We used Mapei's Frost (which is lighter) for a shower floor 2 years ago and you can definitely see darkened grout in the place where I stand in the center of the shower. Apparently the bottoms of my feet must be dirtier than I realize. (Keep in mind I mostly just walk around the house all day on carpeting and clean floors and the bottoms of my feet aren't black or anything.) The darkened grout finally started bugging me enough that I went at it with a grout brush and a neutral cleanser, but I didn't get it all up yet. If I had to do it over, I'd still go with Frost because it was the best color to go with my shower floor tile. I just need to be more vigilant about scrubbing it and not simply doing a quick wipe down.

If you really do want hardwood in the kitchen, I would recommend a site finished floor, meaning the hardwood is unfinished when installed and then sanded and finished. One of the reasons being that when the poly or particular sealer is applied, it seals the seams more so than a prefinished installed floor. I would absolutely also recommended a rift and quarter sawn. You can get this in engineered hardwood if necessary, but if you can, you might as well go with a solid hardwood should you subfloor allow for it. To answer your question of is it a bad choice, that's tough to say. You can always lay some throw rugs in areas where there is a lot of traffic and spills. Just make sure any spills are cleaned up quickly and effectively and if the rugs are wet, take them up and have them dry out. Luxury vinyl is a great choice for the kitchen area. There are many options, styles, colors and installation methods on the market that I'm sure you will find one that suits your needs and style. Luxury Vinyl is very water resistant. However, once scratched, you do not have the option of refinishing them.

DONT go with Ciaro Oak here is our experience...We put Cairo Oak by Coretec in out new build home from flooring liquidators in late 2021. We have 4 kids ages 9-1 and thought a LVP would be the most practical way to go. While I still agree LVP is great with kids this flooring is AWFUL! The color Cairo oak specifically eats anything it touches. Its sadly in our whole main floor so we are on it most of the day. This flooring makes holes in socks and in the knees of pants in literally two seconds. It has become quite costly replacing pants and sock for four kids. It is specifically this flooring. We have had other LVP flooring in past homes with kids and did not experience this. I tried reaching out to Coretec and got a careless response. It is very upsetting to spend such a large amount of money on flooring for a well known brand only to get a crappy quality in return. If you are looking at Cairo Oak from Coretec..keep looking. I wouldn't even recommend the brand after the way they handled their customer service.

Follow their directions for install; it needs to be sealed; it's porous. As for "flaking" is not something that usually happens to limestone.