I haven't had any major issues with the antenna, although I've only really used it around my home Wi-Fi. It occasionally blips and I have some reconnection logic for that but overall it's been fine for indoor use. I have a DIY smart lock and DIY smart thermostat (that literally sit over the real lock and real thermostat -- I rent my apartment so I can't change those out) running off a TinyPICO each and they've been doing fine as far as the Wi-Fi connection goes. They just run a HTTP server on my LAN and I can set the lock and thermostat states with a simple REST API. (I can't stand the complexities around interfacing with Google Home and Alexa ...)
I also used a TinyPICO's BLE interface to connect a phone with a motor driver for a mini telepresence robot [0] though a TinyPICO was probably overkill for this use case. My thinking was really just future-proofing it in case I wanted to add more stuff to the robot.
BTW the Wi-Fi only seems to support 2.4 GHz. No 5Ghz.