I don't think the projects in that question are the same as the ones in your case.
The project's in that question are build projects - they are all different components of the same application, divided into projects for the ease of building and releasing. Such projects, even when placed in different repositories, should share the same project in the ALM, because tickets rarely map cleanly to a single component:
- When you open a feature request ticket, implementing it often requires modification of multiple components. Having to open tickets in all the different projects is not only cumbersome but also splits the design discussion into many comment sections and makes it hard to follow.
- When you open a bug ticket, you can only guess what component the bug belongs to until you investigate - and you don't want to postpone the ticket opening until that investigation(which might be done by someone other than the ticket opener) is done. Also, while not as often as new features, some bugs do need fixing in multiple components.
In your case, since you find it reasonable to have a JIRA project for each project, I'm going to assume they are actual projects, each an application of it's own. If I'm right - you shouldn't put them all in the same repository! It has a very important benefit in the question you referred to - it allows to put in the same commits changes to multiple components that depend on each other. But in your case this is simply not relevant - there is no justification to have commit messages that look like:
- Add UTF-32 encoding support to SuperTextEditor
- Fix weird crash in AwesomeMusicPlayer
- Switch the default browsing algorithm in AmazingArchiver
These are all different changes to different projects that belong to different commits, and there can be no reason ever for you to want to bundle them together in the same commit - these projects should be each in it's own repository.
Putting multiple projects in the same repository is SVN thinking. SVN is a horrible SCM with a terrible design that forces you to use some gruesome hacks or else you won't find the mental strength to resist the argue to leave your 10th floor office from the window instead of the door. Putting multiple projects in one repository is one such hack, used mainly because it's so hard to keep track of multiple SVN repositories. Git doesn't have that problem - so just use separate repositories for separate projects!