/home contains large files... and that is, by default, Trisquels chooses the
XFS filesystem for them! In benchmarks, "small" means tens of kB. There are
many such files in the system. For instance, in /var, I have 11702 files
weighting less than 10kB:
$ sudo find /var -size -10k | wc -l
11702
There are, in the Linux kernel, several filesystem that are specifically
targeting SSD devices. They probably are better choices that ext2.
As for ext4, which is a good filesystem, its choice is usually based on its
stability (it derives from ext3, itself deriving from ext2, and has been
extensively tested) and the availability of many tools for it.
Beside laziness, another reason to prefer less partitions is to avoid the
problem of dimensioning them. Done wrong, you quickly end up with a full
partition while other partitions are almost empty. When facing this problem,
XFS is a pain in the ass since it cannot be shrunk.
