To become a legitimate part of English, new words don't need to be useful, necessary or appropriate. They only need to be popular. As a result, sometimes words we don't need become accepted.
In the 60s, hippies used the word "do" to refer to consuming drugs. "I did a joint" or "Let's do a pipe" were common expressions. The word became so common that by the early 90s, a new government anti-drug campaign said "Do sports, not drugs!" Since my education was traditional, I've never used the word as it is used today. We play baseball or football. We swim or run. We do not "do sports."
"Into" is another hippie slang word that never went away. "I like" or "I take an interest in" would have said the same thing, but to target a youthful reader or listener I might say into instead. "I'm not really into vegetables."
The lexicographers at the OED are the ones who select new words for inclusion in the Dictionary. Their decisions are based on usage, not on need or value. The dictionary is invaluable, but judgement is also needed. Using old hippie slang at a business meeting might not get the results you want.