When Remote Play came out back in 2006, you could only stream video and audio through a PS Vita or a PSP. However, we've come a long way from then! Remote Play was made available on Windows PCs and macOS back in 2016, and support was expanded to all Android smartphones following the release of PS4 7.00 system software in 2019.
So yes, the PS Portal will only let you stream games via Remote Play, but you can also access Remote Play on a variety of devices, including your phone, your computer, and other handheld consoles.