I think Spring Boot is more useful than the MVC, as it has many advantages and inbuilt features which make it more reliable than MVC. In Spring Boot most of the things are auto configured and there is no need of writing those xml as we do in the MVC, which can save time.
Spring Boot bundles a war file with server run-time like Tomcat. This allows easy distribution and deployment of web applications. As the industry is moving towards container based deployments, Spring Boot is useful in this context as well.
Spring MVC is web application framework. While you can do everything in Spring without Spring Boot, but Spring Boot helps you get things done faster.
Spring boot simplifies your Spring dependencies, no more version collisions,
can be run straight from a command line without an application container,
build more with less code - no need for XML, not even web.xml, auto-configuration, useful tools for running in production, database initialization, environment specific config files, collecting metrics.
Basics of Spring Boot can be found here