Yes, there is typically a limit on the number of emails you can send using SuiteScript, which is dictated by the email tier your NetSuite account is on. The “Bulk Merge Email Volume” and “Campaign Email Volume” you’re seeing on the Billing Information page refer to the allocated number of emails you can send in bulk or as part of a campaign.
For SuiteScript specifically, if you’re using the N/email module to send emails, you will be consuming the bulk email limit. It’s important to note that these limits are usually shared across the account, meaning all scripts and email campaigns draw from the same quota. NetSuite’s usage limits can vary by edition and any additional email packages purchased, so you would want to check your contract or speak with your account representative for the specific numbers applicable to your account.