By default, the main user account on MINIX is the root account. Using the root account risks the security of your computer system. It is safer to use unprivileged user accounts, only to become a “superuser” when necessary. Please see Managing User Accounts for more information.
There is always some risk when installing third-party software. Please see the warning in the manual page for pkg_add(1) for an explanation and suggestions to reduce the chance of installing malicious software.