That’s a good question, and I should say up front that I haven’t made a final decision yet. I’m experimenting and will need several months with iPadOS 26 before I know if iPad-only is sustainable for me long-term. What works for me will not work for everyone.I’m in an executive function, not a technical one, so my needs are different.
My work is centered on knowledge management: reading research, writing, preparing presentations, leading meetings, producing communications, strategic planning, and board reports. I review spreadsheets but don’t build them, and I spend a good bit of time traveling, meeting with parents, donors, and faculty. In short, I fulfill the typical functions of a CEO, not a developer or technical specialist. That makes the iPad potentially a better fit for me than it might be for others.
What I like is that the iPad functions as a modular computer. I can type on it with the Magic Keyboard (which I enjoy and find comfortable), switch to the Pencil for reading and annotating, run presentations directly from it, connect through cell service when needed, and place it on a podium for my speaking notes. It’s a typewriter when I need one, a notebook when I need one, and a presentation system when I need one. I also find I can focus better on the iPad than on a Mac, since the environment encourages me to concentrate on the task at hand.
On the reliability side, I use redundant backups. My documents are synced to iCloud automatically, but I also copy critical files to Google Drive and periodically to an external SSD via USB-C. That way I have both offline and off-site redundancy in addition to iCloud. Sensitive documents stay in encrypted storage within the Apple ecosystem, so I don’t need Mac-specific disk images.
As for apps: I use Ulysses exclusively for my book project. For nearly everything else, I rely on Apple’s default apps: Pages for writing and publishing, Reminders for project and task management, Notes for meeting notes, project notes, summarizing research, brainstorming and outlining reports and speeches, and storing quick reference material. Mail and Calendar handle my correspondence and scheduling. I use DEVONthink for OCR and conversions, and EndNote for citation management. This keeps my workflow simple and integrated.
The advantages for me are pretty straightforward: I stick with one platform instead of bouncing between two, the device is always on and ready, I cut down on IT overhead, and I travel with less bulk and fewer accessories. I also prefer working in a single streamlined workflow rather than juggling macOS and iPadOS.
All that said, this is still a test. I may end up concluding that a Mac + iPad combo is the better balance. But for the way I work (as a school head focused on leadership, communication, writing, and strategic planning) the iPad-only setup is looking increasingly viable.
I’m hopeful but time will tell. 
PS: I should add that I can connect the iPad to my monitor so when I need more screen real estate I’m good to go. As to Zoom, it is good enough. I don’t do that many Zoom calls so this is not a big issue for me.