[aaaaaaaaata]

Two viable possibilities:

1. It's about the money, because you never know when you may have a 5-10 year underproductive period due to health/other unforeseen emergency.

2. It's not about the money, it's about the experience/knowledge gained/distraction/self-worth of accomplishing more.

[Joeboy]

> it's about the experience/knowledge gained/distraction/self-worth of accomplishing more

To me, a side gig means accomplishing more of what someone else wants, with the trade-off of being less able to accomplish (or learn about, or distract yourself with) what you want. Which seems like an odd thing to want unless you need the money. I suppose for some people having a £200k income and not needing the money seem less synonymous than they do to me.

[aaaaaaaaata]

Sometimes people see others' goals as helpful to their own.

See: John Carmack at FB.