Is "less good" acceptable?

So I just read "less good" on a random chat...

I think this is incorrect, because less good's "proper" word would be worse, but then I thought: if I say "I aced the exam", it's correct. If I say "I got all questions right on the exam", that's correct as well!

What forces me to use worse instead of less good then?

P.S. I have seen this question, but the accepted answer is not the most upvoted one, so I don't know which to trust! Besides, none of the top answers provide a reference to back up what they say, so that's why I'm asking a new question.

Solution 1:

The Oxford Learners Dictionaries defines worse as, among other things, less good. So I suppose if OLD can use less good, so can we. Still, when comparing two good things I would say:

A 90% score is good, but not as good as 100%.

My admittedly foreign ears don't like the sound of less good than. Google search concurs: not as good as beats less good than 6,000 to 1. This English Grammar advises against less good than on the grounds that "[w]hen making negative comparisons less tends to be used only with multi-syllable adjectives."

Five months later I’m tremendously upset that fickle Google search has not as good as beating less good than 470 to 1 only. I swear it was 6000 to 1 when I first looked into it. Oops, it’s only 17 to 1 in the Ngram. But I include it below hoping it proves more constant. The first few pages of Google books search for less good than return almost only religion and philosophy books. They have more good too (my emphasis):

A degreed property is a property that can be had in different degrees. Goodness is an obvious example of a degreed property. Something can be more good or less good than something else. (David E. Alexander, Goodness, God, and Evil, Continuum, 2012, p. 115.)

Solution 2:

There are differences in meaning between worse and less good.

Pancakes with butter taste good, but less good than pancakes with butter and syrup.

If I say that pancakes with butter taste worse than pancakes with butter and syrup, I mean that pancakes taste bad, and some toppings are more bad, rather than less good.