There's no such thing as "unnecessary" in an absolute sense. The question is "unnnecessary" to who.
"Unnecessary" decorations are necessary if you want something to stand out. If you don't want your house to look like your neighbor's, you're going to make "unnecessary" changes to it. Paint rooms different colors. Use different furniture. All unnecessary changes... if you don't care about them.
You seem to adopt the somewhat naive functionalist/minimalist philosophy that you can find in early modernist thought (e.g. Loos in "Ornament and Crime" [0]).
What those thinkers missed is that beauty and aesthetics are a function too.
"Unnecessary" decorations are necessary if you want something to stand out. If you don't want your house to look like your neighbor's, you're going to make "unnecessary" changes to it. Paint rooms different colors. Use different furniture. All unnecessary changes... if you don't care about them.
You seem to adopt the somewhat naive functionalist/minimalist philosophy that you can find in early modernist thought (e.g. Loos in "Ornament and Crime" [0]).
What those thinkers missed is that beauty and aesthetics are a function too.
[0] https://en.wikipedia.org/wiki/Ornament_and_Crime