The embedded version is, yeah. I was referring to their PC version though, which came with a full-fledged DE called Photon microGUI[1]. It was extremely responsive and could multitask without any stuttering, even on ancient hardware like the Pentium II - something wich other operating systems struggled with for a long time. In fact I would say Linux didn't "officially" resolve the issue until they introduced the EEVDF scheduler with kernel 6.6 in 2023.

[1] https://www.qnx.com/developers/docs/6.5.0SP1.update/com.qnx....