Do I need a Bike computer

Do I need a dedicated bike computer? I've been using a phone bracket and my iPhone running on Strava for the past two years and honestly I think it's worked fine. However every time I see someone with more experience or a YouTube channel (I typically don't follow the lead of influencers) they are rocking a dedicated computer. But it has had me thinking do I need a computer? What are the benefits over my current setup using an IPhone with Strava? Because these things look expensive.