why Swish when BetterTouchTool exists?

Bought a mac after 10 years of working with Windows. Saw that Swish came up as a highly recommended app here and elsewhere. I agree that the UI and the functionality is gorgeous and smooth and what not.

But, I could recreate 95% of the functions that Swish offers using BTT's gestures (with modifiers, but it could be done without as well). Here's a quick view of what I setup (still needs work):

https://preview.redd.it/wdek625yhlce1.png?width=1250&format=png&auto=webp&s=488baa838e44b5e693bfbb2ad2377991c9df775c

Swish would have been the better alternative if they offered a purely one-handed system. One has to still use modifier keys in Swish, without the freedom to change them.

I have to confess that I have spent only a week with both the tools, so it is possible that I have fairly large blindspots. So a question for Swish hardcore fans: what about the app warrant a 12€ fee and what makes you choose it over BTT which is quite the Swiss-knife among mac apps?

Edit: fixed typo