What can be listed as "invited talks" on your CV? I've come to learn (the hard way) that grant referees value significantly the number of invited talks given by an applicant. I'm talking about funding instruments such as the ERC Starting Grant, where the profile of the PI is one of the main criteria to evaluate.

For junior academics who are not "superstars" it's difficult to get invited to give invited talks at conferences. I know have the impression that, at least in my field, most junior academics who deliver invited talks at conferences are doing so either on behalf of or referred by their supervisor/advisor. As a matter of fact, my only invited talk at a conference happened this way, and having recently organized a workshop I've seen this play out in practice.

However, I do get "invited" quite often to give seminars at institutions where I am visiting a collaborator. These seminars can be on the topic of the collaboration or something else: I usually (so far always) have freedom to choose.

I was wondering two things. 1) Would I be misleading people by listing these "invited seminars" as "invited talks" on my CV? 2) Are these "invited seminars" generally valued by the community, especially by those senior academics who are likely to review my next funding application?
Your first question is addressed in the answers to this question mentioned in the comments: Difference between contributed and invited talk

Namely, it is standard to list seminar talks under the heading of "Invited talks", so you should do this.  Some people separate conference talks vs colloquium talks vs seminar talks under appropriate subheadings.  I don't know whether it's standard in your field for junior people to do this, but you could try asking colleagues.  I am in pure math, and I don't, though at some point I started margin symbols to highlight conference talks.

For your second question, it depends upon the reviewer, but in my mind there is some value in seeing a bunch of seminar talks.  It means if we fund you, you'll be active in telling people about the research we've funded, so that's a positive.  It's of course not a primary deciding factor, but grants are competitive so even small positives can make a difference, so it is certainly worth listing your seminar talks on your CV  (assuming you're talking about applications where you send a standard CV, rather than a mini-CV with page/content limits).