It's utterly useless if your browser is 32-bit. Of course, there are other Java applications out there which will benefit having a 64-bit JVM which will allow access to more memory - if you have it.

Java 25 has 17 new features, six of which are at some level of preview. It also removes support for 32-bit x86, with the team stating that "the cost of maintaining this port outweighs the benefits," ...

There are no 64-bit versions of the Java Plugin, Java Web Start or Java Control Panel; however the 32-bit versions of the JRE can be installed on 64-bit systems in order to obtain this functionality.