This Misc Ads area is very important as it allows you to create a tracking tag for anything and everything else that you're doing. You can track the impact of your internal email campaigns, your social posts, niche sites, or anything else that is a media type that is not automated.
The sky's the limit, to create a tag for anything you need, just choose the site, give it a placement name, choose a start date, end date and cost, and optionally you can assign the resulting data to a campaign or leave that blank so that it's tracked in an enterprise campaign. For example if you have a Nursing campaign already and you're creating a tag for a local niche nursing organization post, you'll likely want to assign that tag to the Nursing campaign so that you can easily then see all that data in one place in your campaign reporting.
Other uses of the misc tag feature are that you can tag bit.ly URLs in SMS messages, you can redirect QR codes to one of these tags to see how much QR code use you get at an event and if any of those turned into applies or hires later on. Also you may create vanity URLs for use in print and out of home media, and those can be designed to redirect into one of these click tags so you can track the activity of people arriving to your jobs by way of that traditional media ad exposure.