When an ecommerce has content, but to see it in full you need to click on the "see more" tool, does this have any impact on SEO? If so, what would it be? Does it interfere with reading Google? I can't add examples here, but I think you get the idea.
Search engine bots are very intelligent than your expectation. If any bots crawl your website then he know also about all functions using on website. So if for full information you need to click on see more then bots will check them also. According to me if after click on see more your contens are appearing then those contens will index for sure and it will help in ranking also.
To answer your question, indexing will depend on how you code your "see more" button. Look at this page: https://www.quora.com/What-is-SEO-and-how-does-it-work This uses the "continue reading" button, like your "see more" button. When using browser, in the answers, you will see only a partial answer, then you need to press "continue reading" button to see the whole answer. Now look at the HTML source code of that page. The whole answer is available in the HTML source code. Their is no continue reading button in source code. Full answer is available. Google etc will see this version, not the browser version we humans are seeing. In the above website, they displayed everything in html. Then on page load, they triggered a javascript function, which hides partial comment on browsers. So basically, google saw the whole comment, without triggering the javascript function. It indexed everything. Now look at this other website: https://mncGuru.com/ This also has a "show more" button, like the "see more" button. But if you check source code, it will only show what is shown in the browser. Whole article is not there in source code of homepage. The "show more" button triggers a javascript function, which sends an ajax call to server, then server returns whole article as response, and javascript function displays the full article response on the homepage. But google will not index the whole article on the homepage itself. It will follow the link, and will index the article on its own page. Google says that they process javascript when indexing, and I have seen evidence of this, but I have seen google doing this with basic javascript only. They probably do it for javascript which is automatically processed when page is loaded. I doubt that google processes "onclick" function codes etc...
I replied for what you were asking previously. There are many factors which are or can effect your website ranking like loading time, menu optimization, image optimization, contents of website, inner page linking etc.. To know about all you need to audit your website like GTmetrix.
How does SEO impact businesses? Search engine optimization impacts businesses by improving your ranking in relevant search results. With a high enough ranking, such as on page one, your company can use SEO to bring qualified traffic to your site, which can lead to more leads, sales, and revenue for your business.