I used to use parking domain feature years back when I first started to build my Websites, but then changed to creating add on domains. Much easier to manage, you immediately create a sub-public.html folder and FTP access whereas parked is supposed to just park for later use.
Reason I used parking and then later add-on feature initially was that if my TLD domain goes under for any reason like forgetting to renew, then I won't need to ask the Forum staff to change my primary domain name. So what I did was to use the free host's available sub-domain for the primary domain and then add on my own TLD domains. Strictly speaking it's better to have your main TLD domain as your primary domain as the connection is much better, but I don't mind the little DNS collateral damage if it gives me more power over being in control of my TLDs when something happens.