The logical advantage would be the potential for more exposure and risk mitigation.
The strategy is often used to rank a domain name in the category, and potentially having an overarching/cross-vertical domain that also ranks.
Historically there has been an advantage with leveraging keywords within the domain name, etc... but I'm not sure how much shelf-life that strategy is going to have given the more recent updates.
If you plan to just do category specific domains, a benefit could be the ability to more easily brand and promote the single domain within the niche. Diversifying domains across multiple niches can also help as a risk mitigation technique for algorithm changes, etc.
The downside would be that you are building multiple brands/domains and there is more to manage. You also have to take special care to make sure the sites are unique in content, etc..