Yes, I have an official website for my comic series.
I think it's definitely a good idea to have your own official site for the purposes of:
- blogging news about your comic
- having a storefront
- setting up a links page to help promote your friend's comics/comics you love
- it's more professional/official to have your own site
- it's another place to post your comic incase the platform site your own ends (ie. Inkblazer)
- the ability to feature and post whatever you want
- the ability to customize and design the site how you want
- another place to earn ad revenue on
- you can use it as a hub and post links to all the platform sites you also post your comic on
- and so on.
Other than the down side that it's another site to promote and push, the good far outweighs that negative.