using the MySQL repositories could be an option, but it adds a level of complexity to the deployment and management, especially if one uses a configuration management system based on ansible or saltstack. Adding official repository support to an existing infrastructure management system is a lot more involved than just using the integrated tools. Not rocket science, but still one level of complexity that I could do without.
Furthermore it also adds complexity and uncertainty when one wants to upgrade the system. I know that debian's upgrade system is integrated, tested, mostly works well, and is documented, especially when problems arise. I know I can trust it to do the right thing. OTOH I have no idea how Oracle manages the official repo. Oracle's history track is far from perfect, I know I can't trust them, so I'll have to double check everything. Again, probably not rocket science, but still something I could do without.
Last but not least: I don't know the details, but there is probably a strong reason why most linux distributions took the expensive decision to switch from mysql to mariadb. It cost them development time, support time, and probably many quirks everywhere since it is not a complete drop in replacement. I'll use mysql if I really have to (actually I'm using it since I installed a jessie vm just for era), but it would be much more comfortable and (and IMO) future proof to switch to mariadb.
Oh, one last thing: I don't see the odbc connector in the apt repo, is it somewhere else ?