Firstly, learning gradle doesn't mean you are learning Maven simply because most dependencies use pom files for their metadata. I just means there's a little XML document embedded in your dependencies that 99% of developers never pay attention to, whether they're using Maven or ant or any other build tool. It's entirely irrelevant.
Secondly, Gradle does not require you to learn Groovy. Use Kotlin if that's your thing - I get the impression that's the preferred DSL nowadays anyways.
Sadly I think those are the only two reasons really presented. Neither is especially convincing. IDE support seems just fine for both platforms.
I actually _like_ Gradle and I think I could come up with a longer list of things about it that aggravate me. But either way, use whatever build system you want, and if, as stated, their projects have fairly humble requirements build-wise, I'm sure either system will get the job done.