I know SharePoint is a powerful multi-faceted platform useful for collaboration and that it is obviously very capable when trying to work on a document or spreadsheet simultaneously with other users. But as far as the concurrent use of its file repository feature is concerned, couldn't I achieve the same thing with OneDrive--that is, store files there that can be collaboratively edited in Word, Excel, etc.? Will collaboration break in OneDrive and possibly corrupt a file being worked on by two people at once? Otherwise, what advantages (strictly in relation to multi-user access of its file storage) would a SharePoint Document Library have over OneDrive?
OneDrive for Business and SharePoint Online Document Libraries support the same functionality in terms of co-authoring, versioning, and a few other features. There's no reason you couldn't work out of both, but the intention of each product is different.
OneDrive for Business is designed for your 'personal' work documents, with occasional sharing and collaboration with others.
SharePoint Online Team sites are designed for group-based collaboration, within a team, v-team, department, and so on.
Other than that, for your specific question around real-time co-authoring, you can use either one.