In Odoo 14, i can see that access right for transient model is must. What is the technical reason behind that?

For improving the security of odoo, the access rights is brought for the transient models in Odoo 14. 1.   Wizards do present data to Users. There are cases where you want to prevent unauthorized users from accessing data.  2.  The development pattern should be the same for a Wizard as for a regular model. See this video during odoo experience, explaining the same: Why Access Rights For Transient Models in Odoo14