Search crawlers, user-requested fetchers, and model-training crawlers serve different purposes. A serious policy records which uses the organisation permits, protects non-public systems, and assigns an owner who can review the decision as platforms change.
Technical access is only the front door. Answer engines still need clear service and product information, stable URLs, accurate data, useful internal links, and structured data that agrees with the visible page. If those foundations are weak, allowing a crawler does not make the organisation understandable.