The purpose is so that Twitter is seen as the source of the traffic. A lot of Twitter-sourced traffic comes from native apps, so when people click links from tweets, they usually don’t send referrer information.
If the redirects were server side (setting the Location header), a blank referrer remains blank. Client side redirects will set the referral value.
From Twitter’s POV, there’s value in more fully conveying how much traffic they send to sites, even if it minorly inconveniences users.
I thought about it, but I hadn't originally built it to make money. It was a weekend hack project that I never expected to do that well, and suddenly the prospect of centering my life around a product I didn't really feel passionate about felt like a nightmare. I had a lot of anxiety about whether my external dependencies I'd built on top of would continue to work, and reached the point where a large payoff was worth it to de-risk myself from $23k/mo becoming $0/mo with no exit.
I built a social media analytics API. At its peak, it brought in about $23k/mo, with server costs at about $3k/mo. When I got a job at Instagram, they decided it was a conflict of interest and told me to sell it, which I did for a very healthy six figure sum.
If the redirects were server side (setting the Location header), a blank referrer remains blank. Client side redirects will set the referral value.
From Twitter’s POV, there’s value in more fully conveying how much traffic they send to sites, even if it minorly inconveniences users.