Personal interactions always help your letter.... assuming of course that the professor doesn't dislike you or think poorly of you for some reason in which case why are you getting a letter of recommendation from them?
Which brings me to the point I always make every year.
It is woefully poor to ask a professor or manager (or anyone): "Do you think you would be able to give me a letter of recommendation for _______?"
What you should be asking is "Do you think you would be able to give me a favorable letter of recommendation for _______?"
I can't tell you the number of letters I have read where the reference does NOT recommend the student. Comical for admissions committees to read... and believe me, they have a chuckle when it happens. But they will deny you even if you have a 4.0/99th if they get a letter spelling out reasons why the school shouldn't accept you.
What does the eLOR look like? I have heard others post that their references uploaded a letter for them. From the link below, the eLOR looks like a few questions ranking the applicant and additional space for comments (strengths and weaknesses of applicant). It doesn't really look like a recommendation letter or is the comment section considered a recommendation letter? Just would like to know this before I email my references. Thanks!