> If it's a work necessity, they should consider making a personal assistant a company benefit
I have seen workplaces with concierge service for employees to handle personal tasks - I'm actually surprised this isn't more popular. Tech companies definitely are known for meals and snacks and coffee being provided, I think that is in the same direction.
To your question, scheduling meetings and travel can be a huge time suck, especially for a CEO that would have lots of both and rapidly changing plans. Logistics for meetings - "party planning" can be a big job and depending on the size of the company there may not be someone separate to do that.
Personal stuff like changing addresses, filling forms for whatever, waiting to have a mattress delivered (I had a former boss send an EA for this), anything where you have to be on hold on the phone. All this admin stuff only increases as you get busy, and it would be great to have someone to deal with it.
Plus there are always special projects - pulling info together for a presentation or something, looking for a vendor for something. I think I'm talking myself into hiring one...