Internal business applications are going to be a lot clunkier than a publicly available web interface.

The reasons are typically:

1. They are designed for a few number of users, so they can automate an internal task. The application seems complicated and uses a lot of language specific to the domain.

2. Generally under invested in. These are great learning projects for people to do, but it also means the implementation will probably be substandard. Work arounds will be discovered for the known bugs, since the users all in the same company anyway. These projects reduce OPEX/COGS, they don't directly contribute to Sales/Revenue, so they aren't as important for the company.