Right, but investing our time in PCMCIA, a technology from the late 80s, is not going to help a lot in that regard. Machines with PCMCIA are old and probably not so well suited to run Haiku anyway.
Even Linux is starting to remove it: Linux 6.4 Slated To Start Removing Old, Unused & Unmaintained PCMCIA Drivers - Phoronix
They are planning to keep CardBus which is closer to PCI and does not need as much support.
So, that’s the first question: is the hardware you want to use based on Cardbus or old style PCMCIA? In the latter case, as I said, not only you have to do the “hotplug” support (even if it is only a simplified version that scans the card once at boot), you probably also have to do the ISA plug-n-play initialization, which we never did in Haiku because it started its life in 2001, and by then, ISA cards support was already on the way out, and so no one felt a need to implement that.
Cardbus is possibly a bit easier, since it is PCI and we do supprot that. And the hotplug support would not be unwelcome, since it is also reusable on ExpressCard (hot pluggable PCI express) and Thunderbolt as well as some laptop docking stations.