I thought about it, because it was a point of discussion in the Rari infra team funding : the main reason I see is that it offers a longer-term commitment for the recruits. To me having a 4-year visibility with my vesting was important, because I knew I was not leaving my stable situation for something that could be over a few months later. It sets the good mindset that you’re committing for the long term. In practice as an employer the risk is the same, because if they don’t deliver you can always fire them after 1 year, but as a recruit the perceived risk is smaller, because you know that if you are good, you can stay for a long time 
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