In such a case, a client knows that the developer might create a site for one of the client's competitors. In other cases, a client might be introducing the developer to a new industry. In such a case, the client might want to restrict the developer for a reasonable amount of time from creating sites for the client's competitors. This can be accomplished through non-competition and confidentiality provisions. In the course of a long and expensive project, it might occur to a client to simply terminate the development agreement and hire away one of the developer's key employees to complete the work.
Developers can contractually restrict the client from doing so.
When a company depends on its website for a large portion of its business, then it can incur large losses when things do not go right. Developers can contractually shield themselves from liability for such losses. To avoid spending a lot of time and money resolving these issues, the parties should resolve these issues in advance in the agreement. Not all issues can be anticipated and covered in a website development agreement, especially given the speed at which the technology is changing. Nevertheless, both parties are best served when important issues are resolved early on.