Hi Andreas,
Yes you can fire-up the WP-cron with a server cron-tab but it will have some, probably unwanted effects. Let me explain:
The plugin is processing the product feed in batches (750 products per batch when you are running PHP 7 or higher). It does so in order not to run into memory issues. Batches are triggered using the WP-cron, once a batch is done it will automatically create a next job in the WP-cron which almost immediately kicks of the next batch of products.
Now if you trigger the WP-cron, lets say every ten minutes, with your external crontab the job the batches will be idle for 10 minutes each before it can process the next batch of products. As a result it might take very long for your product feed to complete. This can be problematic when for example Google is retrieving your product feed at the time it is still being created. This will result in a lot less products in your merchant center.
Hence, we would advise you to enable the WP-cron.
Hope this makes sense?
All the best,
Eva
