if you have the money and ability then why not ?
They may have the money but not necessarily the skill, they have paid to sit there.
BA, Thomsonfly,Ryaniar, Easy, Jet2, First Choice, thomas cook etc etc, all do line training on their 737/757/320 fleets for low houred pilots
But that actually IS line training with a view to keeping the cadet as a long term employee who will become an experienced pilot. What Astreaus and others are doing is not line training, its hour building! After the cadet has his 100, 300 or 500 hours its time for the next wannabe to take his place.
So the ONLY difference is that the person in the seat is paying instead of getting paid.
Well that's a BIG difference.
pro·fes·sion·al
1. a. Of, relating to, engaged in, or suitable for a profession: lawyers, doctors, and other professional people.
b. Conforming to the standards of a profession
2. Engaging in a given activity as a source of livelihood or as a career
3. Performed by persons receiving pay
4. Having or showing great skill; expert
Its the difference between a professional pilot and an amature.