Speaking from experience: even if a software product is not freely licensed, there is immense value in source code being available and - better yet - modifiable (whether directly or through plugins) when trying to troubleshoot issues with that software or integrate it with other software or adapt it for your business' needs. Further, if your company's finance department is worth its salt, any such customizations and integrations are assets with real value, so even if your company's engineers are "wasting time" tinkering, the company can - and should - still capture this value on the books.

And further speaking from experience: with relatively few exceptions, I've found enterprise software vendors to be pretty much useless in terms of support, and to be more often than not an obstacle to business operations than a value to it when things go wrong. All for a pricetag that doesn't even come close to justifying their meager SLAs (that they'll inevitably weasel their way out of anyway).

The decision to use transparent software is more often than not a decision in the best interests of a company. Transparency is a dependency of trust; without that transparency, you have no real way of knowing whether you can trust your business on it.