History of “-ish”

Just to be clear: we are not discussing the "-ish" ending of words like abolish, punish, which comes from French.
"-ish" in the sense of "somewhat" is recorded in the OED as far back as 1894/1916
The alternative is to use the French version: "-esque" .
"Ish" has become a new standalone word in British English, meaning somewhat.

Yes. Sorry for the confusion.
What I mean by "ish" is the "ish" I saw on a note fastened to a local store's locked entrance door that claimed they would return in fifteen"ish" minutes to reopen. I have also experienced the statement made, "That's cool'ish'". When I asked someone where something that I was looking for was I received the answer, "it's around'ish'". I understand its meaning but why the need for it? Is it laziness? Has it become so pop culture that now it is in common use in our languages? Do we fear committing to the very statements we make? "Ish" to me implies a lack of confidence. Call me old fashioned, but when a store owner used to claim they would return in fifteen minutes they, more often than not, would. But a store owner claiming to return in fifteen'ish' minutes means they could either return in fifteen, twenty, thirty or sixty minutes. There seems to be no accountability in "ish".

@Philip
Never seen or heard "ish" used in the manner you describe.
In my experience it's more commonly used to mean "around" or "about", as in "What time will you arrive?" "12ish"

I also heard it with reference to color, but that sounds okay to me. Like, the color is "greenish", do describe something between blue and green or between brown and green to say that it has a hint of green or that it's kind of green but not completely, you know what I mean?
But 'coolish' and 'aroundish' sound awkward to me. I think it is better not to overuse it, it sounds annoying to me like this...