The following document provides comments on tiles and more specifically, the flexible tile partitioning feature discussed in recent meetings. The authors assert that the idea of generalizing tile partitioning to allow for tiles being split into units smaller than a CTU may sound simple conceptually but has a significant impact to implementations and wish to express significant concern with the implications on frame compression, virtual pipeline data unit processing rate, in-loop filters and on-chip memory access overhead. Therefore, it is suggested that the topic be more carefully studied, discuss whether tile functionality without splitting into smaller CTUs is already sufficient for applications such as 360 and frame packing video which may not be as prevalent as traditional 2D video and/or consider alternative techniques rather than flexible tile partitioning.