Oh good question Janet! I guess it would depend on lots of factors…
Biggest one being, are you a solo VA or a team? Teams will be able to provide more services than an individual and therefore it allows the client to be more flexible with their workload e.g. you might have graphics, typing, bookkeeping, SEO, and copy writing skills in the team, whereas it would be unusual to get all those skills in one person, so no one employee would be able to provide all those things. Likewise if you are a team and get 24 hours of audio in one day (this has actually happened to me a number of times!!) the team would be able to type it, whereas a single employee would not be able to. So if you are a team, it probably does still make sense to have a VA rather than an employee.
Second question: What is the workflow like? If it is an unusual blip in their usual working pattern, having a flexible admin resource is sensible, because it lets them scale up or down the hours, rather than having a fixed number of employee hours. e.g. if their usual employee is on maternity leave, if they have a project which last for 3 months but then goes quiet, if they are growing and aren’t sure about sustainability of a role.
Thirdly - if this isn’t an actual client, do they understand how VAs work? We get this all the time - people come on and say “I need a VA for 20 hours a week”. They don’t actually mean that, because they are used to having on site employees who spend half their lives making tea, clearing emails, faffing about with paper jams etc. One recent study by VoucherCloud says that UK office staff work as little as 2 hours 23 mins a day! What they actually mean is that they want the facility/availability of a VA for 20 hours a week, and it might mean 5 hours actual billable work.
Hope that helps!