A Wallet like this will be of particular concern to hackers, they will definitely keep an eye on the Nunchuk wallet, especially a gap (cloud) which the hacker can be entering it freely. Many beginners today want something practical and don't want to be complicated to keep the seed and the private key, even sometimes they know if more complicated to keep the seed offline is safer, but they ignored it. This situation is utilized by the developer to make it practical and make a new environment by cloud.
And, certainly, a market like this will keep growing in the future, but on the other side, we will continue also in the future to read a new thread about: Help my wallet being hacked in the cloud.
Hackers will spend more efforts to hack into a system because they know that if they succeed, they will get big data and big money. Oppositely if they hack a person, what they get will be smaller if they don't know what that person owns. I am not discussing about targeting like a millionaire or a billionaire, just a random person and reward should be small even if you successfully hack into an individual device or account.
Because of potential big things from a system hack, hackers will aim at systems like cloud storage, a corporate data base and similar big systems. I agree that storing sensitive personal information, wallet seed, wallet passwords in cloud is bad. It is worse when it is done by a big system, a wallet and I don't advice anyone to do this individually.
Using Nunchuk wallet and accept that risk, it is your choice. I don't choose it because I have better wallets without risk from cloud storage, backkup. I am fully responsible for my keys, my backups and my coins. I am fully aware that if I lose my keys, my backups, I will lose my coins but I don't want to lose my coins because I trust a third party and it fails to serve me.