Being willing to pay a high price to be considered nice is of little use. Computer operating systems should be user-friendly not thinking people. Instead of being locked into niceness and the detriments and pitfalls of being nice and unable to make a strong decisions. There is a grip on what the nice person perceives as being nice-image that circumvents a very rich, even abundant part of life. Standing alone! Standing in the minority opinion can be a character building experience of epic proportion.
Then enters kindness! It is a word that has not morphed or changed over the centuries. Its meaning has been consistent and true. It is easily identifiable how it’s being used in a sentence in context of the written sentence. There is no need to know the person, context, voice tone, or the social context to understand what being kind means. There is no confusion or extra information needed to know what the word kind is really meaning.
As far as a descriptor for a person, I never want to be a nice person. However, I do want to be a kind person. As a nice person I am trapped into a certain expected behavior. There is no latitude for thinking or decision-making in being nice. There is however a trap that you must always do a certain set of behaviors in order to keep your nice status. This is equal to doing anything to keep your popularity or likable qualities to Attempt! AKA manipulation of others to like you. (AKA self-righteous) Nice can approve wrong to keep the nice status.