We only keep them for debugging purposes and attack prevention. The maps layer (visualization) is done from an external company though: you can change this in the upper right corner to e.g. the original OpenStreetMap or Thunderforest.
Additionally you get nice biking and hiking routes all with elevation, multiple other vehicle types like scooter or truck. And the possibility to export to GPX or using multiple via points. Additionally we try to update the road network as fast as possible (currently max. 1-3 days) from OpenStreetMap data, which is not always the case from other providers. Currently we try to revamp our UI to integrate new features like our alternative routes (you can trigger this via algorithm=alternative_route URL parameter).
Now it is always important to ask the question "how do they make money?" and to understand why we can offer this all for free and even have the routing engine as open source: the simple reason is that we do not have to earn money with the end user. We created the company to push our open source projects (we also have jsprit - a toolkit for solving rich vehicle routing problems) and we try to support OpenStreetMap where we can (e.g. we are the only European corporate gold member of the OSM foundation) and do this via our growing SaaS where we sell subscriptions to many small and medium sized businesses. We do not have VC and so there is no pressure into things we don't want.