Being in the outsourced Accounting world we use Intacct two different ways. First, our organization uses it for our own internal accounting software and second we recommend and use Intacct for our clients when it is the best solution for their business.
For our organization, it is used by the entire company. Our accountants (employees) use it to enter their time to allow for management to keep track of hours spent on each client with a quick click of a button. Team Leaders receive emails telling us when the time is submitted and then they review and approve accordingly. The Director of Client Services and the Accounting Manager use the time to create custom reports which help us to see if we are profitable for each client and Team Leaders can view to see if all time is submitted properly and if a client's price may need to be increased. We also use the Tech Change Order feature to help us manage price increases needed as well as utilize requests for refunds, etc. This all helps cut down on internal emails and back and forth, we can put requests right into the system and the accounting manager can process with ease when its time to do the billing.
For our clients we use it for their accounting. It is hard to say exactly what it is used for since we have clients in vast array of industries and all use the software differently. The best thing I can say is that the custom reporting really helps for consolidating reporting. You are able to create reports with ease and they are very functional.