No, the approaches of iTalki and HelloTalk are completely different.
In italki you can book and manage face-to-face lessons with professional or amateur Japanese (or other languages) teachers. The website offers convenient scheduling and profiling tools, but less chatting functionality. Once you have found a teacher that you think suits your needs, you make an appointment. During the following skype (or other video chatting software) sessions, you can basically do, whatever you both find suitable for learning Japanese. When you feel uncomfortable with your teacher, or do not agree with his/her approach, you just make an appointment with a different teacher, next time. Lessons typically cost something between 10$ to 25$ per hour, which is defined by the teacher and is generally based on the teacher’s experience and competence. Most teachers offer free or cheap trial lessons and support pre-defined learning paths of the different textbooks on the market. But generally, what you make of your lessons is up to you.
HelloTalk, on the other hand, is more of a social network optimized for language learning. The focus is much more chatting and sharing content. Moreover they implemented a convenient tool for correcting other people’s contributions, highlighting mistakes and marking correct formulations. There’s sort of a public pinboard (“Moments”), where everybody can publish text and photos with the purpose of getting feedback from others. And there’s also a friends list and a private chatting functionality. Full subscription gives you more possibilities in terms of your own profile and unlocks some additional features.
For some people HelloTalk might feel a little bit frustrating and difficult to get into direct contact with other people in the beginning. Especially when you just subscribed, are a male non-native english-speaker and are a little beyond the age of the average Japanese learner (as myself).
In my experience, what worked quite fine when starting HelloTalk, was to spend some time in the “Moments” section, getting used to the environment, commenting on and correcting some posts to “earn some credits” and the contact requests and interesting conversations will come eventually.
To conclude this unexpectedly large post, I recommend both tools, since they are both effective and they serve completely different purposes. And I think it is never too early to start with italki, since private lessons are always a very effective conversation practice, given you find a good teacher.
However, I myself am still stuck with WK, Bunpro, Human Japanese Intermediate and Genki II, so I postponed them for when my schedule gets a little less cramped.