Each project is different and while many folks—like myself—love to use and prefer Webflow, it’s definitely not right for everything. If your client has needs that go beyond the platform then by all means, use another platform.
While this other platform looks similar, they appear to be fairly new and I wouldn’t even think of trusting it for any serious projects until I knew more about them. There’s little to no detail on their infrastructure or who they are as a company (I can only find that they’re based in Portugal)—two things that are important to me when I trust a platform with a client’s project.
I prefer to invest in tools that have proven to benefit and help grow my business, not jump ship every time I see a shiny new toy. I’ve learned to utilize other (trusted) tools outside of Webflow if the project has a needy set of requirements, but all of them have been around and shown that they won’t go under before the years end. Not to mention you can always pair Webflow as a design tool with the backend of your choice—not every site needs to be hosted on the platform.
If you’re serious about web development as a career it may be wise to think of the tools we use as a partnership that work towards the benefit of your clients. It doesn’t benefit anyone to jumping ship when something else comes along without first at least testing it out to see if it’s as good as it claims to be.