Who here agrees that if someone owns an A1200 that he should never buy this?
You have to remember what computing was like when this device came out. I had a friend who owned one and there was a good reason for it: Price!
Back then, 2.5" hard drives were bloody expensive and this thing allowed you to add a 3.5" drive for a fraction of the cost (nobody thought about cutting shielding and bodging wires). If I recall correctly, the 3.5" drive over the PCMCIA port also out performed slower 2.5" internal 2.5" drives (correct me if I'm wrong).
As for Internet, it was more about bulleting boards via a trusty old dial-up modem attached to your serial port.
The only other thing the PCMCIA port was good for back then was expensive RAM cards and a squirrel for adding a SCSI hard drive and/or one of those new fandagled CD ROM thingies, but that was only after the CD32 was released. Most of us added RAM via the expansion port with a CPU card.
Yeah, today I wouldn't touch it with a barge pole, but it has its place in history and was useful when it was made.