That is what it boils down to and has for years, what is most popular and will lead to the most infections. Infect that. That is why Internet Explorer and windows were the main targets for drive by downloads. Not that many internet connected tv's out there at the moment, no point spending time getting those infected.
Again you have to differentiate between a targeted attack and mass infections. If you are targeting an individual then everything is useful and it could be beneficial to sniff Netflix logins in case the same password is used elsewhere like email. If you are after bank logins it's a numbers game and you try and infect as many people as possible knowing a percentage of those installs will give the goodies, while the others can still be used for DDoS, sending spam, ransomware or other activities.
Plenty of Android malware on the play store disguised as Antivirus software and Android is a very lucrative platform with a large number of potential victims. Some custom roms (particularly Chinese/China based) available for download are pre-rootkitted so are well hidden from being spotted too. Gonna get worse before it gets better
