Subdomain is a sub from main domain, and many businesses do not like to use subdomains because they feel a subdomain give disadvantages in many ways, e.g. being ignored by bots and index spiders in search engine (SE). Fell look less professional if compare use main domain and so on.
Actually subdomain does not matter if you utilize it, which is important how you select the right keywords that several community search with few rivals, and are able to optimize those keywords using search engines optimization maximally. If you can act it after that no crisis you use your subdomain, because SE spiders and bots will still index and give traffic to your subdomain
You are able to make every subdomain as a separate category when you own to submit to search engines, by doing this you still achieve a subdomain with excellent rankings for each subdomain will be seen by SEs as another website with the homepage or the index itself. You are able to also try to start subfolders on subdomains so that SEs can interpret the folder as a set of site information.
If the primary domain backlist affected then this will affect the subdomain, because the subdomain is considered a part of the primary domain name, there are several citizens who feel worry about this issue where they are banned subdomain due to problems with the primary domain name, for example in adult content web site own violated sure agreements that they’ve signed with service providers that don’t want a domain that is utilised for adult material, but if used correctly in domain name and does not violate the existing rules, next you are supposed to not worry if you would like to utilize a subdomain.
Therefore there is no problem to use a subdomain If you would like to build up every subdomain as a separate identity from a website, but if you do not want to use a subdomain, then you can use a domain name by using a certified landing page