Renault interested in Esteban Ocon because he's "fast, reliable and cheap"
F1 News
It is being rumoured that Esteban Ocon will replace Nico Hulkenberg at Renault for the 2020 season and this is something that the French team would accept. Not only would the team have a French driver racing for them but there is a major financial reason for them preferring Ocon. If Mercedes loan Ocon to the team then the German team will be paying for some of his salary putting less strain on Renault's back pocket.
RMC Sport has reported that "The French manufacturer is very interested in Ocon, which has the advantage of being fast, reliable and cheap. With the very large salary paid to Daniel Ricciardo, Renault would not be opposed to a reduction in labor costs.
"By taking Ocon instead of Hulkenberg, it would happen. When Renault returned to Formula 1, they had made the German driver a priority and therefore overpaid a little."
It seems unlikely that a company as big as Renault would be worried about the cost of drivers but to have someone will the skillset of Ocon at a reduced price would be ideal.