Good
The benefit of these apps (or website builders) is that you can get your website up and running probably within a day, even if you don’t know how to code.
You install the theme, change the content on the website, and that’s it. You probably think, “Yeah, easier said than done”, and while that might be true, it is extremely easy to use if you decide to learn it.
Another awesome thing is the community around these tools. There are a lot of tutorials, forums, and people that you can ask for help on pretty much any issue you have.
The community also maintains plugins you might need. A huge number of plugins are available for free, especially with WordPress, since it has existed for a long time.
There are marketplaces where you can buy more serious themes for your business that you can customize as much as you want. These are great for providing a better experience for your users than free stuff you can find. And the best thing is, they are pretty cheap.
Bad
Because themes and website builders are designed to be “one size fits all,” they come packed with sliders, animations, and layout options you will probably never use. Behind the scenes, your website is forced to load thousands of lines of unnecessary code just in case you might need it. This leads to a slow website and high loading times, which frustrates your users.
Another issue is that Google penalizes slow websites making it harder for your website to rank at the top of search, which is a goal if your website is necessary for your business.
Plugins are somewhat of a double-edged sword. While you can use them to create almost any feature you want, they just add a ton of code to your app, which slows your website down. Before you know it, your website is composed of 20 plugins made by 20 different developers, and sometimes those plugins will slow down other plugins, which can be quite a difficult thing to fix.
Cost
While you can have your website up and running practically for 0€, there is an issue that all of these websites encounter, and that is scaling.
They will work great when you don’t have any users, but since these websites are made specifically for a wide audience, they need to have a ton of unused features which slow down your website. You mitigate this by upgrading your server to a better one, or you go to hosting that is specifically tuned for the tool you choose.
Those platforms (especially Webflow and Squarespace) lock you into using their infrastructure, so you can’t just go and say, “I will take my code and go somewhere else”, as that is not an option.
For example, the website you are reading this on is actually running on a server that we are paying about ~4€ a month for. But since we don’t pay a lot for infrastructure, we had to build it manually from the ground up and optimize it so it can run on pretty much anything we put it on. Of course, at certain point we will need to upgrade, but even then, doubling the money and server power, it still would be ~8€ a month, which is really cheap.
Verdict
Website builders and templates are incredible tools for hobbies, testing a quick idea, or getting a brand new business off the ground on a tight budget, which is a totally legit option.
But once your business starts growing, that template becomes a bottleneck. When performance, security, true customization, and owning your own digital real estate become priorities, the “cheap and easy” route usually ends up costing you more than actually developing your website from the ground up with actual developers.