Unsure about Devolving

Hey im likely going to buy and play the game after work today, I enjoyed the demo a lot!

However I am unfamiliar with digimon in general and with the games, so I was wondering how important it is to devolve and reevolve your digimon. It was sort of mentioned in the demo but I'm curious if it's something I should definitely do. I kind of missed what it does and I am a bit confused.

It reminded me of EV training in pokemon which is not at all necessary to beat the base game, but can be done if you're doing a challenge or are a perfectionist, so im wondering if that is the right interpretation!