I mentioned above that native apps are a different story, especially on iOS where there really is no other option at this time. PWAs are also a different matter. If you are using PWAs on iOS then pasting your nsec may be your only option. Not sure if nsec.app might work for that use case. Either way, I still wouldn't recommend pasting your nsec into a client if it can at all be avoided, regardless of how much you trust the developer. It's a matter of how cavalier you want to be about your nsec possibly being compromised. I have been around here long enough to know that even the most well-intentioned devs in this space make mistakes that can compromise users' private keys. Hopefully we will see a signer app for iOS developed that will work similar to Amber, and which can be used both for native apps and PWAs. I saw that @Terry Yiu is going to be making this a priority.