[kitsunesoba]

I have a 2008 Dell workstation laptop (M4400) that had the swappable bays feature that I bought used around 2012 and used as my primary machine for several years (which as an aside, worked so, so much better than buying a brand new machine for the same price would've).

In my case I swapped the optical bay for a SATA bay which enabled quick swapping of SATA drives. For my usage at that point in time that ability was very handy… perfectly possible with an external USB gadget of course, but it was nice to have that without the cables and gadget. Most of the time that bay held a large HDD for "cold" storage, allowing the primary SATA slot to be filled with a fast 256GB SSD.