I'm sure that will be the case for certain companies. For companies who routinely deal with PII, PCI, or other regulated data the security teams are likely to be much more worried about the potential for sensitive data to be inadvertently shared outside of the company. Even if it is communiques about only business sensitive matters (e.g., iPhone 12 XXL release) that is not something very security conscious companies will be happy having in the hands of a third-party without an appropriate security review.

Having run a security program at such a company, at the minimum I would expect a SOC 2 or ISO 27001 audit of your company before I would allow my company to utilize your services as it is tightly integrated to our internal communication platforms.

This isn't to say you need that now but you should understand there are segments of the potential customer base that will not work with you without being able to pass that level of scrutiny.