While browsing the web, sometimes you want to search for something mentioned on a webpage but just want to look for it on a pre-determined website - not a search engine. Bangs are great for this if you're already on the search engine's website. Otherwise, you could highlight, right-click, and search for the text with your default search engine. However, it would make it more conveinent if you could search with bangs straight from the context menu.
The browser extension could add a group of options to the context menu when text is highlighted to "Search with bangs". In the group, there would be options to search specific sites or settings that have been inputted in the extension's settings. For example, in the extension settings you could add !yt or !de then those options would appear in the "Search with bangs" group in the context menu.