Well, I wouldn't even though I'm also a remote developer working in SE Asia for a company on the other side of the world. However, if it helps you do what you need to do, then it's absolutely worth it. Time zone issues are killer. I can't tell you the number of meetings I've missed because Japan doesn't participate in the daylight savings time dance. Google calendar is a bit better than before, but the UX is still actually pretty uncomfortable when you are trying to think, "What time is that for me and what time is that for them". (Incidentally, there is a new feature in Slack where when someone messages you it tells you what time it is for them -- this has helped me a couple of times).

I hate calendar apps generally, so like I said, I'm not going to pay for one. But I can definitely see paying a measly $50 if it comes with UX that helps out.

Having said that, I found the article a bit heavy on app recommendations and light on actually useful tips for working remotely (especially remotely in a very remote timezone).

Google GSuite is about $15 per user per month for Enterprise, and most users only really use Gmail, Calendar, and maybe Drive. That's more than $50 a year for a calendar.

So... lots of people!

Spending $50 on a work tool that you will use many times a day actually sounds like a great deal to me.