The app is doing an http(s?) request, which includes more round trips than a simple ping. Also, the web server may be more loaded than the ping response would indicate.
Usually not. I got a similar "ping" page on my website but haven't found a browser that closes the TLS connection between secondly requests. Also built a websocket version but that turned out to only be useful as canary because it doesn't survive connection changes.
If I ping apenwarr.co I get consistent results:
Pinging apenwarr.ca [74.207.252.179] with 32 bytes of data: Reply from 74.207.252.179: bytes=32 time=203ms TTL=51 Reply from 74.207.252.179: bytes=32 time=202ms TTL=51 Reply from 74.207.252.179: bytes=32 time=205ms TTL=51 Reply from 74.207.252.179: bytes=32 time=202ms TTL=51
And on my mobile, on the same network, my blue blips look normal enough. Just not on my wired desktop.