Smart Home: Is a gateway necessary for Tuya and Gosund-compatible devices?

Hello, I recently got my hands on temperature and humidity sensors smart home wifi, compatible with tuya smart life, etc. I use with the application Gosund, do not need a "gateway".

I want to buy more equipment "smart" and so I wonder whether to go in the direction of gateway => devices, or skip the gateway and buy what is available and works on wifi ie to the router ? I am a bit green on the subject and would like to ask if I will lose something by not having a gateway ? Or only that it is known that if the device I am interested in is only on the gateway it will not work. Without a gateway it's less of an option or something ? Because as far as I can see, everything is controlled by the application ? Greetings

If there is a gateway, they usually work on a different - more stable and more economical (battery-powered) protocol, e.g. Zigbee.
For the Zigbee protocol you need a gateway, but thanks to this the devices have battery power and it lasts up to 2 years, some people make such a gateway on their own on Home Assistant, if you do not want to share your data with the Chinese cloud.

When they work via wifi it is rather rare to need a gateway, because such a gateway is simply your router. But still your data goes to some Chinese cloud.

Zigbee also has the advantage that mains-powered devices communicate with each other to form a mesh of connections.In my own place I have appreciated the advantage of this, wifi does not reach everywhere.

Thank you for the valuable information, I have done some reading on the internet and I already know something. Due to the fact that I already have devices on WiFi, I will now only test their battery life and decide what to do next in some time. Best regards