I realize it takes more time and I used an agent for my first apartment but after that I drove around areas I liked and wanted to live and just called directly. It can save you money.
You are in the drivers seat and most (not all) owners will negotiate.
I've tried working with a few real estate agents using Whatsapp and have had mixed results. They're responsive, but so far each has only sent me 1 apartment. Maybe my criteria is too narrow...