Compatibility of SD-Card-Readers with Ipads or Iphones.

I have been using the set-up seen in the picture below for quite a while in order to use External-Storage with my Ipad (Air, 3rd gen.). It's an Atolla USB-A-3.0-Hub [item 3 in the picture] which connects to the Apple Camera-Adapter [item 5 in the picture] and thence to the Ipad. When it's all connected up the Camera-Adapter receives power from the Apple 15W (5.2V, 2.4A) power-supply [item 7 in the picture] and the Hub receives power from its own 15W (5V, 3A) power-supply [item 1 in the picture].

The Lexar SD-Card-Reader I'm using in this way [item 2 in the picture] doesn't explicitly state on its packaging that it is compatible with Ipads or Iphones—though it doesn't say anything to contrary either—: it just states that the system-requirements are "Mac OS 10.8+; Windows 10/8/7/Vista/XP; USB 2.0+ port", and I couldn't find anything further about it on Lexar's dysfunctional website. I have tested it and when doing so it seemed to work—reading and writing files with the Ipad—without any problems in this set-up. Am I fine to keep doing this? Is there any reason why this SD-Card-Reader would not be compatible with Iphones and Ipads besides the obvious physical USB-A-connection issue, which the set-up in the picture works-around?