It's beneficial to have someone to bounce things off of, to provide feedback, or to share a degree of personal information; it can be helpful for my manager to know that I have a lot of family stuff going on this week so I may be intermittently available, less productive, or working different hours.

It's also an opportunity to get on the same page about stuff or clarify things that might be a bit too long-form for a daily standup.

My 1:1s with my team lead vary between three minutes and 45 minutes; if there's a lot to cover, we cover it, if there's only one thing we discuss it and hop off. If there's nothing or if one of us is busy we just skip it.

I think the real benefit is that that time in my team lead's calendar is always blocked off for me if I need to use it for something so I don't have to wriggle around other meetings, appointments, etc. to get a slice of face-to-face time about something that doesn't feel 'important enough' to schedule a meeting for but which wouldn't get discussed otherwise.