The poll says nothing about exFAT. Here is the poll... https://together.jolla.com/question/...-jolla-tablet/ It's asking which open source filesystems should be supported. I took it as read that exfat was mandatory and the alternative filesystems were for the Linux fundamentalists.
Given that the legal status is as described in update 4 of this request, I suggest the following: Support SDHC (up to 32GB, no exFAT licensing). With a user installable package, support: >32 GB formatted with btrfs, and optional LUKS encryption. If possible, paid-for exFAT license package to support SDXC ...