Specific algorithms search engines do not like to advertise, so in many respects the answers to seo-questions are fuzzy, blurry.
So in your case, the recommendation will be something like "make a site for people, not for robots - and then you will have good performance in the eyes of search engines." And by the way, first of all you are thinking about how the site will be evaluated by search engines.
Try to understand: from the point of view of an ordinary visitor, is there a difference, the description of your service is made on the blog page or on the site page? This will actually be the key to your answer.
From a purely technical point of view, for a search engine there is no difference what page to index - http: //site.tld/blog/kuplya-zolota or http: //site.tld/kuplya-zolota/ - this is not important for him. , and then just the url string.
All this "other things being equal." That is, if you have a template for a curve and, say, on a blog page, it automatically generates a title tag (not at all what you need), and on ordinary pages you can put a title more flexibly. But CNC is a thing that is completely quietly turned on everywhere.
Personally, I would prefer to make a separate page, but it is pure flavors. I fully admit that posting in a blog can be licked to the state of "candy", there would be a desire and diligence.
In fact, behavioral factors currently have more influence - how much time the user looked at the page (how interesting is the service), how many failures, etc.
So focus on exactly things that are interesting to the user, not the search engine.