P2418HZ video conferencing monitor cabling

I have just bought one of these to use with an old Dell Inspiron M301Z laptop, which has a mini DisplayPort connector. I bought a mini to Displayport adapter as there wasn't one in the box, and I'm hoping to get it going tomorrow but....

One day, I'll want to replace the laptop, and I notice that few if any Dell laptops have DisplayPorts any more.

As I understand it, DP is preferable to HDMI. So would I lose  functionality?

I know that DP also carries audio, and that's going both ways on a videoconferencing monitor. But I don't know if this monitor uses the DP or the USB cable to carry audio, when it supports its onboard speakers, microphone, and audio in/out sockets.

Can anyone confirm whether I must seek out a DP-capable replacement laptop, or whether a HDMI with USB 3 one will be just as good?