Ligatures are old fashioned in English but still very common in French. Some ligatures are actually mandatory (like the oe in cœur, heart) while others like st are pretty common in proper typefaces such as those used for novels. The author is probably French (Aurélien).
I've been writing almost exclusively in cursive for my entire life past age 8 and that font looks crazy to me. I learned both D'Nealian and Zaner-Bloser in different schools and have seen a lot of my grandmother's writing, which was semi-Spenserian.
The stroke just doesn't go in the right direction for those ligatures. My guess is that this font is based on a French (or maybe other latin) script.
But also French typographical ligatures (well beyond the syntactic ones that are mandatory) aren't really related to cursives, they are a typographical convention. like the cursive s doesn't look like s and wouldn't have a ligature with t from the top of the t in cursive. (However, at least for French cursives it's common to do a single cross for double tt which I guess is a ligature?)
I also only learned cursives in school. In fact writing in script was forbidden and not taught at all.
