Disadvantages of a direct coupled preamp?

I have a Sonic Frontiers Line 2 preamp. I was thinking about sending it in for component upgrades, so I thought I'd read about the different coupling capacitors available. I then learned that my preamp is direct coupled.

I read about several benefits of direct coupling such as better low frequency response, less smearing, less coloration etc.

I want to know what the disadvantages of direct coupling are, particularly if anyone knows details of the implementation in my Line 2. If direct coupling was the bee's knees, wouldn't all high end gear do it?