Earlier quoted context omitted.
As a startup you have less leverage to access proprietary datasets. In fact, most of the companies we tried to work with wouldn't let us even access the data, let alone use it, unless we did everything on prem. Oh and one company even wanted to own half of our IP.
Your algos, pipelines, UI and UX might be the best but you still don't have the data to make it worthwhile on its own. If the dataset is really that good then giving a 50% stake (not necessarily the IP) might be very well worth it. It just comes down to the terms of the deal.
there's almost no scenario I can think of where giving up 50% of your IP is worth it. there would be almost no way to raise vc funds to hire more researches or devs.