Yes, you're right. The interface looks similar. Functionality is different though. While codesearch, implement full-text search, ClassCrawler is about relationship graph and search in it.
https://classcrawler.prettyclear.com/?q=%7B%22fullName%22%3A%20%22AbstractCo...
https://classcrawler.prettyclear.com/?q=%7B%22overrides%22%3A+%7B%22%24in%22...