Span reverse not working on variable

static float AsFloat(byte[] buffer, int offset, bool isDataLittleEndian) {
    float value = Unsafe.ReadUnaligned<float>(ref buffer[offset]);
    if (BitConverter.IsLittleEndian != isDataLittleEndian) {
        new Span<byte>(ref Unsafe.As<float, byte>(ref value)).Reverse();
    }
    return value;
}