Good evening, @Lamine 
That’s a great initiative! 
As to professional benefits, you may want to have a look 
at this thread: Community Recognition Program. Please let us know if you have specific questions.
In case you want to focus on other kind of more personal benefits too, TWB provides us with an opportunity to have a positive impact in the world, by playing an important social role in the world. 
By joining TWB, we can help bridge language gaps, and translate information that will, in some cases, actually save lives. This is specially true if a translator speaks languages like Pashto, Hausa, Dari, Amharic, Bengali, Sylheti, Tigrinya, etc.
I will tag here our kind @sifatnoor, who was recently been featured by The UN Office for the Coordination of Humanitarian Affairs (OCHA) as an Humanitarian Hero. 
He may want to say a few words on this too. 
But even if a volunteer only speaks two or more of the ‘mainstream languages’, they can still translate information that will make someone’s life better, or help them somehow. 
Coronavirus made it clear how important it is to have accurate information on our own language. On a crisis, you need to know what to do - but everyone was at a loss when it began. It caught us all off guard.
I remember when the lockdown started here in Portugal. People were afraid of each other; they weren’t just being careful. They did not know what to do, so fear overpowered them. At the time, I was looking for a job. Suddenly, I was expected to stay home, unemployed, so I wanted to help somehow. When you think of a pandemics, you think of doctors and nurses saving lives, or you think of a brilliant team of researchers finding a cure. I have none of those skills, but I realized I could help by translating Covid-19 related projects into Portuguese.
Right now, the number of new cases are rising again in Portugal, but people aren’t so afraid as they were in the beginning. And the reason is because now they have information that allows them to understand better what’s going on, and they also know what they need to do to protect themselves and others. And it means a lot to me that TWB has given me the chance to contribute a little to make that fear vanish, and to replace it with, if not always reassurance, at least some degree of understanding.
So, what I can tell you is this - having the chance to be a TWB volunteer translator during such an unexpected and surreal crisis helped me create a meaningful routine and to stay positive at a very uncertain time. It also made much more confident and resilient in general.
So, in a nutshell, there’s a lot of benefits.
By the way, Lamine, when you have your video ready, 
please share with us. Also, I’d be happy to provide European Portuguese 
subtitles. 
Again, thank you for this amazing initiative. 
Have a great evening, Lamine! 