We get addicted to things which release happy harmones in our brain with less effort.
Online gambling is more addictive because of factor like these:
Ease of access: we can start playing with just our phone laying on bed. no need to take effort of going down stairs, driving car, etc.
Bonuses: we get a lot of bonuses on thousands of online casinos.
Availability: online casinos are available 24 hours anytime we want to play just log in to any casino with our phone.
but there are many disadvantages also of online gambling like we cannot control ourselves to gamble responsibly, our mind not trust 100% to online casinos, etc.
One of the biggest disadvantages of online casinos is that there can be scam casinos which a person might not be aware of and once they make an account, deposit some money, and start gambling, they later find out when the casino doesn't allow them to withdraw their funds if they manage to get some wins, and that is how the person loses their money even after winning. And this thing doesn't happen with physical or land-based casinos since someone won't create an establishment only to scam people, they also can't do that without a proper license.
However, the points that you mentioned are true. Ease of access is the biggest reason why online casino platforms have become so much popular, especially after the pandemic when land-based casinos and everything else were closed down and people were doing everything online.