IMO, it is better to have antivirus than no protection at all. However, antivirus software only help with Malwares and Virus. The users have to be careful with phishing website and take responsibility for the private keys.
It is better to have free anti virus that premium paid anti virus because it is also like just wasting your money on something which is not going to secure from that things what we are talking about.Android are always prone to malwares even if we have anti virus due to our allowance of third party apps from unknown sources so you can have IOS for more security.