Thanks for the feedback! I originally had it like you are suggesting, but I moved to the current version for a few reasons.
When it works in game (rather than in map), it can cause issues where if you are walking towards a chest, click on it to open it, but because you were too far away, it opened in remote mode, and now you can't transfer items. Ideally it would disable remote mode when you get closer which might mitigate the issue somewhat, but I don't think I ever implemented that. This is why there is a message and sound - to make clear to the player that they were still out of range and the current GUI is only being opened remotely, with all the item transfer limitations that that entails.
I went back and forth over what the default should be for that setting. In the end I went for the default that causes the least surprise to players. Some people using this mod will be doing so because they got it as part of a modpack (e.g. Exotic Industries Official Modpack) and don't actually know that they have it. I was seeing people report 'bugs' to EI because they couldn't pick up items in chests. The people I asked on my discord agreed that it should be off by default - it makes a clear separation between normal play (in game) and remote play (in map). The 'advanced' mode is available for players like you who want it.
Maybe since the 'advanced' mode is opt-in, I don't also need the clarifying message and sound... but I still think they are useful to make clear when a GUI is opened in remote mode. I agree that the alert sound is quite harsh - if you'd like to suggest a better sound for me to use, by all means. I found it quite hard to find a good alert sound that I liked.