Yes, you can use the iTracker360 JS snippet if you do not want to install the WordPress plugin.
What does the WordPress plugin do? The plugin is very simple. It only includes the JS snippet on all of your WordPress pages (excluding any wp-admin pages)
Why would I not use the WordPress plugin? If you have all of your tracking codes included in one spot, such as Google Tag Manager, or some other area in your theme, then you might want to keep all these codes together in one spot for easy management.
Is there any advantage of using the WordPress Plugin? Not really, the only advantage that I could see is that we exclude the tracking snippet from being loaded on any wp-admin pages which is useful at times.
If you are using WordPress, at the end of the day, I would recommend just using the WordPress plugin, but if you don’t want another plugin installed on your site for whatever reason, then feel free to just use the JS snippet instead.