A thought: The goal of task management is to understand what you should be doing right now. (Apply to appropriate values of “you” and “now”.) Task management that doesn’t help you reach this goal is waste.
So backlog items only bring value when they help you (or someone else) decide what to do now. Those 50 items at the end of your product backlog? Probably not very valuable.
Different project management activities handle special cases of “understand what you should be doing now”. Their value depends on the situation.
For example, a detailed schedule might help you decide when to start marketing efforts before release. Or it might help you decide which features to include in the release. But if your marketing efforts have a short lead-time, if the most valuable feature is obvious, and if you do continuous releases anyway, then perhaps the schedule doesn’t bring that much value.
I hope this thought will help me decide what level of planning to do in different situations and find alternative solutions to the problems planning is trying to solve.