You cannot use MODX Connect without the driver.

If the class driver is sufficient depends on what you need.

I'm not sure if your usage includes a DAW. Folks who use DAWs tend to really like what Connect provides to them.

The reverse question may be reasonable - what's the downside of installing the Yamaha Steinberg USB driver on your system? That's not a rhetorical question (compatibility with other installed drivers/software? something else?).

Core Audio provides an elegant and reasonably efficient intermediary between recording software and the audio interface driver. It supports essential features like multi-channel operation and does not add significant latency of its own. Mac OS even includes a built-in driver for class-compliant USB audio devices which offers fairly good performance, so many manufacturers of USB interfaces choose to use this rather than writing their own. ... Historically, this stands in contrast with the audio handling protocols built into Windows ( https://focusrite.com/en/news/system-science-part-2-drivers-latency )

I ask this particular for mac, if the steinberg drivers offer an extra benefit over core audio. (e.g. latency, reliability).

Given your answer I gather there's no downside so install them to ensure full operation with all features.

On the audio side the Steinberg drivers give you buffer size customization. I'm not sure if the class compliant Mac driver allows for this or not.

WebMIDI may need the drivers (for SoundMondo) - I'm not 100% sure here on the Mac. On Windows you need the drivers for it to work.

Otherwise, I do not have measured data for latency. Maybe there's information out there on the net somewhere. Installing the Yamaha Steinberg USB drivers shouldn't increase latency. That's somewhat speculative.