It would have been absolutely criminal if you hadn't been awarded the $500 bonus cheque, Alvin.
According to Axios, Medium has something like 725,000 paying subscribers. At $5 per month, that's $3.5 million subscription revenues. Paying $500,000 in bonus cheques every month is a huge ask, since that's 14.3% of revenues, without taking into account Medium Partner Program payouts.
I feel the bonus cheque is probably a stopgap measure meant to reward high engagement writers while they transition to a new model for rewarding writers. I guess the new model will have longer-term incentives, more of the form of "$100 per month for 5 months" rather than a one-off $500 payment.
But, rather than direct payments, I really hope "investing in writers" means more resources spent on promoting content written by independent writers. I'm guessing they're already looking at this, seeing they're featuring more independent writers now on their Instagram and Twitter channels.