Lets first understand that what is Beta Testing - when a set of Users are testing an application in pre-launch phase, to collect the Users feedback.
So, if these users will find a Bug - These users will not have access to Bug reporting application and also, can we ask an user to write the detailed of Bugs (summary, Description, attachment, steps to reproduce...), ideally NO.. then how the bugs are reported - So users are reporting the bug in brief format or we need to understand the behavior of issue. We will then replicate the same scenario in our local environment and then we will log the bugs. For example if you sign in amaazon app a Beta tester, and you find a bug.. so Will amaazon give you the access of the bug tool to log the bug.? Probably no... Remember during Beta testing application is strictly monitored by all the team and each error and exception is analysed thoroughly.