I bought one of these as well, they're really nice and you can add a SATA 2.5" SSD in addition to the M.2 NvME SSD.

I would suggest a second hand laptop or mini pc, is a better alternative for many people

But is good to see the ecosystem of projects that rpi generated

Second hand laptops are usually bigger, have a screen (maybe broken, so why not go for the SFF), and often due to this more expensive as second hand. Harder to open, maintain, and for thermals.

I prefer the Lenovo Tiny as they use a lot of the same parts as their notebooks, and are smaller, more stackable. I had 5 M93p machines for OpenStack development. Still use these machines for my son's workstation, one as a router/firewall, etc. Only one thinkpad for work as I can drop that in my bag for travel, but otherwise I have only Tiny ThinkCentres... TB3 for external graphics card.

I even take an M-series I5 n my backpack on travel as you can power them with a Slimtip USB-C cable, bluetooth Thinkpad keyboard (dual connectivity option) and an external USB-C screen for notebook/tiny. They are amazingly versatile and easy to maintain as parts as interchangeable. Can't say this about most MiniPCs, such as NUCs.

Forgot to say, they are cheap as chips when bought second-hand or from an execution sales. If it wasn't obvious... I love them!

Interesting that it has a battery, that works as a nice "UPS". And monitor mount useful too

How does it support TB3 graphics? only example I can see is extended PCI. Or just for the thinkpad?

Also how can the tinypc support the USB-c screen?

Can't relate to the fan noise issue at all - my intel variant is essentially silent.

Any links to a version that contains 16GB and costs 115 euros inc tax ?

Should be tons on eBay, upgrading RAM is also easy so don't worry about finding one with 16GB if the price is too high.