I think you misread, the delays are if you don't use instant delivery. I use it and it's extremely consistently delivered instantly, which makes sense, it's a websocket.
As to battery drain, I'm sure it technically does consume more, but according to my phone it's an insignificant amount: <1% of usage which is the lowest stat it gives you. Their docs suggest the same thing:
> the app has to maintain a constant connection to the server, which consumes about 0-1% of battery in 17h of use (on my phone). There has been a ton of testing and improvement around this. I think it's pretty decent now.
Honestly it's a good solution that works well with few downsides, the only real one is that iOS doesn't support doing it, but personally I don't have any apple phones so I do get an essentially free lunch.
As to battery drain, I'm sure it technically does consume more, but according to my phone it's an insignificant amount: <1% of usage which is the lowest stat it gives you. Their docs suggest the same thing:
> the app has to maintain a constant connection to the server, which consumes about 0-1% of battery in 17h of use (on my phone). There has been a ton of testing and improvement around this. I think it's pretty decent now.
https://docs.ntfy.sh/faq/#how-much-battery-does-the-android-...
Honestly it's a good solution that works well with few downsides, the only real one is that iOS doesn't support doing it, but personally I don't have any apple phones so I do get an essentially free lunch.