Access to the development database as apps user for the developer is as same as heart for a person. Without the access to the apps user, there is always a possibility of the access issue. Even though most of the issues may be resolved by grants, it is easy for Oracle Support to solve the issue as the apps user.

Most of the time, the access to the application server itself is enough for the EBS developers, since there will always a team of DBAs support the database issues. If the dump directories used to create the trace files are mounted in the shared drive and the application server has the access for the same, then there is no need for the developer to have the access to database server.

Access to the application server as applmgr always comes handy to get the source code, to conduct a proof of concept (POC), validate the code pack before submit to DBAs for migration etc.,. Most importantly, applmgr is the right user to make any changes to the application. If there are any issues, then Oracle Support will be able to help. It is developer's and the team lead responsibility to not to miss use the applmgr user. The recovery of the development instance may take few hours to a day, may cost high overhead.

The developers are not setup as the regular users in the production instance. To reproduce the issues in the development instance, it is required to have the similar setup as the end user. Sometimes, we may even have to login as an end user in the development instance to find the details of the problem. As same as applmgr in application server, "System Administrator" is also having lot of power. Obviously, the responsibility, and the power comes as a single package. One without the other is either dangerous, or useless.

A developer may get some idea about solving an issue at any point of time. This may be the main consideration to provide the remote access to the development instance. Remote network access always comes handy in emergency situations.