I think that it is better using InfinityFree than social networks. If I create my website, anyone with internet connection can visit my website. If I use social networks, the visitors need to register, add me as friend or follow. Social networks are used by spammers, trolls, fraudsters, criminals, terrorists… People need to consider unknown people as friends on Facebook and similar social networks. Infinityfree has many features like creating blogs, forums, image galleries, social networks etc which many social networks do not have.
A very good point! While social media can be a good marketing tool, using it as your main business is dangerous. Social networks can decide to change their policies and pages at any time, which could ruin all your precious branding. So having your own website is still very important today.