SBCs are becoming more popular because one of the prevailing patterns in designing complex embedded systems is to do the real-time control on a microcontroller running on bare metal or maybe an RTOS, and the GUI/database/web connectivity on an SBC running Linux. It's been happening for at least the last 20 years and becoming more popular because the hardware keeps getting cheaper and cheaper.
If your system cost can absorb it, this gives you a huge amount of flexibility and capability.
If your system cost can absorb it, this gives you a huge amount of flexibility and capability.