Buy an apartment as SIAL (Société immobilière d'actionnaires locataires)

Hello,

I’m a long time reader of this forum and this is my first post, thank you in advance!

I’m considering buying an apartment under the legal form SIAL (Société immobilière d’actionnaires locataires). I’ve found some explanations online, like this one: https://realadvisor.ch/fr/glossaire-immobilier/societe-immobiliere-d-actionnaires-locataires-sial

In practice you buy some shares of a “tenant company”. It seems though a quite outdates system, compared to the more standard PPE.

What should I be careful of? Are banks offering mortgages for this?

And of course: should the apartment be sold at a discount given this legal structure? How much discount would you expect?

Thank you in advance!