Is there any benefit of being treated as "professor" by students and admin?
A certain amount of separation from your students has value. You have some power over their future, for example. The use of usted implies respect as well. This is useful if any conflicts arise in the future where you need to take a role of authority.
But, having a friendly and open relationship with your students is also useful if it gives them the "permission" to seek you out for help when they need it. Mostly I'm thinking of academic help. Even if they have personal problems (health, family,...) it is useful to them to know that you understand difficulties that may affect their performance. You can encourage them in such situations.
Sometimes you need to be understanding. And sometimes you need to speak somewhat strictly. Both can advance their educational pursuit. Less frequently you need to speak with full authority. Don't make that impossible, should the need arise.
So, a small gap is useful, and too wide a gap is probably not optimal. There are some students who will try to take advantage of you (e.g., by trying have you change grades) if you seem too much like "one of the gang".
Note that I was always Dr. Buffy or Prof. Buffy to my undergraduate and even MS level students. But with doctoral students I (and my colleagues) more or less insisted on first names. But the expectation was that they had achieved the status of colleagues at that point and we wanted them to think that way.
Another element to consider is the point of view of students : in some cultures the students might be very uncomfortable calling you by your first name (and even if it isn't an issue in your country it could still be for international students).
I would recommend "allowing" your students to call you by a formal title even if you allow them to use your first name.
It depends on many things.
What is the general culture at your university? You should at least be aware of how other faculty approach this situation. Being the one person who does things differently might be your style. But maybe you should consider that it gets you talked about, and not in a good way. At least until you have tenure.
For undergrads, you will probably be in a superior or supervisory position. Is it possible you will be in the position of giving a student a failing grade? If there is some misbehavior on the part of a student, might you be the person (or one of the people) who decides on punishment? If you are friends with your students, this sort of thing can be a problem, even a conflict of interest. One of my previous bosses once told me that being friends with the people you supervise is a potential issue should you ever need to discipline one of them. If you had to expel a student for cheating, but you were friends with him before the cheating, that could be a very sticky proposition.
Grad students, especially PhD candidates may be somewhat different. Under most circumstances, they have been filtered very strictly before they get to such a program. It is often as big a reflection on the prof and the faculty if a PhD candidate fails out of the program. A PhD candidate is in transition to the level of a prof. Introductory, bottom step on the ladder, not there yet, but transition.
As well, a prof supervising a PhD candidate is going to be interacting closely for at least 3 years. So there is more potential to be more nuanced, and more expectation of commitment and involvement.
So for grad students, generally it will be less of a problem to be friends. I visited my prof's home several times during my PhD. But I never saw the inside of any of the homes of my profs during my undergrad. I went drinking with my PhD supervisor on numerous occasions. We discussed various sensitive topics that I would never have thought to speak to a prof about during my undergrad. I mean, I held my prof's less-than-one-year-old son while he went back into the house to get something.