Yes Discord is real-time chat.... audio, text, and even video. Ideal for live conversation with a friend group or gaming team
But it is becoming more and more common for a Discord server to be dedicated to a discussion topic, with open invitation
For example there is a public MMA Discord with 44,000 members. you can log on and talk MMA in a much more immediate way than Sherdog
Many subreddits have their own Discord communities, so a topic has a built in user base
Of course the signal-to-noise ratio is worse than message boards - You must put up with a lot more nonsense.
But that is the nature of the internet now. faster and more noisy than the message board era.