Travel apps are they all the same?

What do you want a travel planning app to do? If it's to store info, then you would have to have an account.

I tend to use separate, specialized apps and web sites to go directly to, for instance, accurate train schedules, local transit schedules, etc. Google Maps is the only thing I use that even approaches a more comprehensive online resource. I'm old-fashioned like that. See also https://www.ricksteves.com/travel-tips/phones-tech/apps-for-travelers.

Define "safe." Depends on your preferences for privacy of your personal information. Some people are perfectly willing to expose all their location and contact information in exchange for free "services" provided by apps. Others are not. If you have a smartphone, you are already giving away a lot of personal information whether you think you consented or not. Many times I see the people who exclaim loudest about loss of privacy or complain about what companies do with personal data are fine with downloading the latest app. You really can't have it both ways. You might be able to use a paid version and have a bit more control over your preferences but I'd guess most any travel app will ask for access to your locator service, so they'll know where you are and when, ostensibly so they can send you notifications and updates when you travel. I'm not expressing a preference either way, I just work in an industry where I deal with this almost daily. If you don't want to accept their terms of use, including the privacy notice, then don't download the app.

I will be traveling as 3 adults headed from SFO to Venice then Florence and Rome. Looks like multiple airlines and multiple cities over 2-3 weeks.

Will the app schedule and watch flights, schedules, and changes?

Is there a better app?

It is difficult to compare other apps with the one you are looking at when we don't know which app it is that you are investigating.

We could just guess but I doubt it would be helpful

I like Tripit for the organizing - you forward confirmation emails to it and it makes a great easy access schedule

What app are you talking about? And why be nervous? If it doesn't do what you want, delete it.

I don't know of an app that will schedule and watch flights, schedules, and changes. Do you mean a fare watch from airlines? Or, if you're referring to the time after you book your flights, you could get the app(s) for the airlines you're using for this trip or you could sign up for texts/emails from the airline for any changes or updates. I use Tripit to keep track of my reservations, but I think that only the Pro version will send you updates. I've never worried about my apps being safe, nor have I heard of any problems with security.

I am not sure I would trust an app to keep me up to date on the flights and changes. I have the Delta app, I am a SkyMiles member, I always sign up for emails for my flights BUT there have been times when I have not gotten notification of Delta schedule changes.

Tripit does alerts with flight changes, gate changes - has worked for me

It is difficult when the person posting the question doesn't come back to clarify the question.

Guessing is much like blindfolded darts.

Precise questions and responses to clarifying questions yield custom answers.