I feel quoting a topic relating to DDOS protection, in a topic relating to spam protection, is quite disingenuous. The comment made by Charles was a direct response to cloud accounts having WAF protection automatically. This is still the case, and will always be the case, and is not related to spam protection entirely.
And as I said previously, hCaptcha has been proven to be more effective. Whether or not you choose to use that, is of course entirely your choice. I understand that you may find that users do not like captchas on your site, but they also may not like to validate their email and just click through. If you remove that, it will also add to the issue. Its a question of balance. If you wish to check if someone is a real user, you have to have methods in place to do so. Captchas are one of those methods.
Feel free to add specific suggestions to our feedback area for items you wish to see added to the platform. These items for example, were added as a direct result of feedback from a number of channels
https://invisioncommunity.com/news/invision-community/new-spam-prevention-features-r1284/