When it comes to research, I found Japanese research labs to be very impressive as they have world-class state-of-the art facilities. Typically in American research-oriented universities, there are common shared facilities for the use of specialized equipment and tools where your lab has to rent its usage. In Japan, it is common for each lab to own their own equipment/tools and even an entire clean room, which is very convenient for long-term use.
You also get to develop great professional relationships with students, post-docs, and staff members while further grooming and enhancing your research skills. Depending on your department, there are weekly mandatory research seminars where students present their own research progress and also give a brief overview of different research areas. As a presenter, you get the opportunity to learn and practice your presentation skills (both oral and written). All of the Professors and students attending your talk will give you a written evaluation of your presentation, so you get direct feedback from everyone on where you can improve for your next presentation. Another great benefit of this seminar is that you get exposure to other research labs in your department and can learn new ideas from other student presentations that you can apply to your own research project.
As for attending academic research conferences, you have the opportunity to attend both domestic and international conferences. For the conferences in Japan, if your language skills are advanced or if you are looking to develop and improve, you can choose to give your presentation in Japanese. Overall, there are plenty of opportunities to practice Japanese in an academic and professional setting, which you would not get back in your home country.
In general, the first year as a MEXT scholar is very busy with acclimating to the country and preparing for the university entrance exams; however, after transitioning into a degree course, you will have plenty of time to enjoy the beauty of Japan as a country.