A recent example is that we replaced our support ticket system with an in-house built one. The new system lives in the same database as our app. Every ticket now has real live customer data. You can't get this kind of integration easily using a 3rd party tool.
It was surprisingly easy to build. Just took 2-3 days for us. Massive improvement in productivity. Took about $100 in tokens to build. Maybe an hour of maintenance work per week.
This larger company took 48 hours: https://tradecore.com/resources/blog/we-replaced-zendesk-in-...
Doing this would've be seen as crazy in 2023. But in 2026, it's often an advantage. Better, more integrated, cheaper, faster.
I'm happy to buy if it's something I know we don't have the expertise to build. For example, you'll never catch me saying we need to build our own database. But for something like Fin, I know exactly how to build it for my company and I think I can build a better agent with better context, faster iteration, cheaper, and more tailored to my company's business.