I had a look at the publons webpage, a website for tracking academics such as peer review, editorial contributions etc. They claim that it could be used for promotions and funding.
Being a Ph.D. student, is it worth getting an account with publons?
I think it is particularly useful as an early-career researcher with all your reviewing ahead of you. I've also noticed assessors really appreciating that Publons can now verify all of your reviewing and editorial work, which can set you apart from others who just say they review for some journals.
If you want to be considered for more reviewing assignments, then it's a nice way to get your name in front of journal editors as a potential reviewer too.
Can't see the harm if it's free and easy to maintain...
This is ultimately a subjective question, but one can ask: what is the value added of publons? Or better, what is unique in publons that is not found elsewhere?
In my understanding, the answer to the latter is none. As a PhD student and early career researcher, you should at some point have your own personal website. Furthermore, you should have an account with Google Scholar. And, something that is quickly emerging and soon to become the standard in academia, you should have an ORCID account. The latter is your unique ID as a researcher, with links to all your research. ORCID is a system developed by a non-profit, academic oriented organisation, and ultimately, it is an open source, community base project. Importantly, they also allow you to add peer reviewing activities, something which was unique to Publons (but not anymore). I can testify that in my academic institution, an ORCID is required, as it is used for departmental evaluation.
I tend to disagree a bit -- though I agree this is contentious. For someone like me, at least (an early career researcher) who has a LOT of balls in the air, publons offers, if nothing else, a convenient way to keep track of the reviewing I've done. At the end of the year, at the time of Annual Reviews for my institution, it is an easy cut and paste job to let them know the level of my 'academic service' for the year.
Many of the 'extras' on publons (like rankings, and 'excellent' reviews) I have not yet found to have any value. As an ad hoc editor, I could imagine that it might provide me with ideas for reviewers... but I haven't used it in this way yet.