On the same page it's clear they log a lot of data on their users. Except as and only to the extent expressly permitted in this License or by applicable law, you may not copy, decompile, reverse engineer, disassemble, modify, or create derivative works of the Bluestacks Software or any part thereof.' REF:

You may make one copy of the Bluestacks Software in machine-readable form for backup purposes only, provided that the backup copy must include all copyright or other proprietary notices contained on the original. The Bluestacks Software may be used to copy and/or install and run Android apps, which you are authorized or legally permitted to copy and install, from your mobile Android device to your personal computer.

'This License allows you to install and use the Bluestacks Software. On the 'Graphics' settings page, you will see the following options: Graphics engine mode: Here, you can choose between the two available modes, Compatibility or Performance. On the Settings page, click on the 'Graphics' tab. No modifications allowed anywhere in the license. Open the 'Settings' menu by clicking on the gear icon on the Side toolbar. Their terms and conditions only allow you to make one copy of the software for backup purposes only.

Bluestacks root setting