IMO, Kubernetes is one of those things where if you have to ask, you don't need it. It's only really "justified" if you're actually using features like:
- High availability services (more than one copy running at once).
- Service discovery (services talking to each other in a resilient way).
- Ability to automate operational tasks.
- Rolling deployments of services.
Very few personal projects will tick those boxes -- by the time they do, they've usually evolved into a full-on "real project".
Doesn't mean you can't mess around with Kubernetes for fun and learning, of course. But from a purely practical perspective, it's overkill unless you have all of those requirements above. (If you just have one or two of those needs, there is usually a simpler tool to fulfill it with less overhead).