I never understood under what circumstances you would really need a custom font. Could you say more about why that was the case?

Both Netflix[0] and the company I worked at designed custom fonts to _save_ money. As other comment threads say, it's a standard practice to license by pageviews, and it can be difficult to negotiate. Alternative: just have your own custom font, exclusive and unlimited license.

[0]: https://www.theverge.com/2018/3/21/17147170/netflix-sans-cus...

...but was it cheaper than just finding a suitable free font(s)?

However, if a design team wants to make their own font and has the resources to do so I don't see why not. It's a strong branding move.

The problem is that for these companies, they're in danger of being burdened by copyright issues, as somehow everyone forgets that designs are copyrightable in Europe, and unlike programmers most designers don't really want legal uncertainties when it comes to their designs (because it's damaging in their circles). If they're designing from scratch, they hold those design copyrights and designers can rest easy knowing that they won't get sued.

It was cheaper than licensing a couple of fonts we liked. So we asked the designer of one of these fonts to tweak their font to our brand, and license as new IP under new name. Because it wasn't entirely "from scratch" the price was reasonable, around $50k.

Video Games is an example, each AAAA games I worked on had custom fonts (that was used in-game but also for our powerpoints presentation during the making of the game).

Woah, quadruple A games? Did you work at The Initiative?

Likely branding. For example, Coca-cola can write pretty much whatever they want on the can and you'd still know it was them because of the font.

I'm just guessing, but based on the description (Microsoft, wearable, tiny screen, specific DPI) it sounds like for the Microsoft band: https://en.wikipedia.org/wiki/Microsoft_Band

Microsoft Band, curved screen, tiny DPI, and we initially were using raster fonts, not true type. 4 bit alpha for anti-aliasing.

Primary glyphs were hand hinted, with glyph of each font size custom made to fit on our grid.

For v2 we ended up using Monotype's awesome embedded font engine that let us have real true type font rendering in just kilobytes of RAM with a 96mhz CPU. Insanely cool tech, I believe we were the first adopters of it, we helped them optimize a fair bit of the underlying engine code, and fixed some bugs along the way.

Still a custom font file though. Both the true type and raster fonts were variants of Segoe, Microsoft's main UI font. We wanted it to be on brand, but also look great on our screen.

So tl;dr that is why the MS Band 2 had really good looking CJK glyphs and it is how we pulled off anti-aliased fonts on a tiny LOL CPU with next to no RAM. :)

A distinctive font can be very recognizable, just like a logo, colour pallet and other parts of a house style.

I've recognized fast food places abroad with the logo text translated into Arabic or Cyrillic by the font.

Why your font choice matters:

https://pimpmytype.com/open-sans/