In my opinion, in a company with many diverse products and desire to better integrate them I think it makes a LOT of sense to implement a single point of contact (and failure of course!) for all authentication matters.
In our business our IdentityServer4-based implementation will underpin key strategic projects going forward. The benefits are:
- Simplified implementation within your products since they only need to talk one language to one service
- Enhanced security as it's much easier to manage and ensure quality in a single authentication solution. The protocol designers have done the hard work for you too.
- Enhanced user experience due to true single sign in and out and consistent UI etc.
OpenID Connect also supports a diverse range of use cases so problems that may have once required clean-sheet home-rolled (and probably flawed) solutions can now utilise standard flows and be rolled out with little more than just configuration.