@meraki Yes. i have done it multiple times. The flag just tells the script to add ERPNext as part of the site install but if you remove it, ERPNext will not be installed only Frappe. to be specific:
This line:
bench init frappe-bench --version $bench_version --verbose --install-app erpnext --version $bench_version
change to:
bench init frappe-bench --version $bench_version --verbose
and this line
bench new-site $site_name --db-root-password $sqlpasswrd --admin-password $adminpasswrd --install-app erpnext
change to:
bench new-site $site_name --db-root-password $sqlpasswrd --admin-password $adminpasswrd