Hello Alex
Strictly speaking, in order to pass the exams for certification, it is not necessary to purchase physical equipment. Having said that, having and working with physical equipment is always beneficial compared to working in a virtual environment.
The first reason is because there are some features that you can’t simulate, such as VSS, Stackwise, IGMP snooping, and Cisco DNA center to name a few. Secondly, real equipment will behave as expected whereas simulated topologies will always have the possibility of a different behaviour as shown in this post.
But the most important advantage of using real equipment is simply the fact that in your career, you will be dealing with real equipment, and no matter how good a simulator gets, there are some nuances and aspects that can never be simulated. I’ve had the good fortune of working at a large university and a large municipality, both of which had extensive Cisco-based networks, and the experience gained on real life equipment and setups is incomparable to that obtained on simulators.
Don’t get me wrong, simulators are more than enough to build and hone your skills, but nothing beats real equipment to gain real-world experience.
I hope this has been helpful!
Laz