The expansion cards seem pretty gimmicky to me. You're replacing a hub with... a bunch of hubs with one port on it. I know it opens up to some third party modules (this one seems particularly cool: https://github.com/LeoDJ/FW-EC-DongleHiderPlus) but for the most part you are getting less connectivity than other laptops. You don't even get an audio jack without taking up one of your expansion slots (edit: on the Framework 16. 13 includes it).
If the expansion slots were larger then they could have maybe facilitated something like getting 2 usb-a ports in exchange for the one USB-C which feels like an actual thing to consider. As it is, it just doesn't feel like you're gaining anything. If you're carrying any additional expansion cards with you you lose the only advantage it has over buying a hub, which can turn that one usb-c slot into multiple usb-a ports, ethernet, hdmi, audio, sd card reader, etc.
If the expansion slots were larger then they could have maybe facilitated something like getting 2 usb-a ports in exchange for the one USB-C which feels like an actual thing to consider. As it is, it just doesn't feel like you're gaining anything. If you're carrying any additional expansion cards with you you lose the only advantage it has over buying a hub, which can turn that one usb-c slot into multiple usb-a ports, ethernet, hdmi, audio, sd card reader, etc.