It's a sign that people are serious.

I dread free trials of computer software. Some software might cost $500 or $9 a month, but evaluating the software might take 2-3 days (say 20 hours) at a fully loaded rate that could be $100 or more ($600). Maybe the probability is 50% that you want the software in the end, maybe the probability is 50% you can convince management to pay for it, so there is a 75% chance that the evaluation time doesn't lead to a purchase.

When that task gets added to my agenda with other tasks that have a near 100% chance of being useful, that evaluation is my lowest probability so the free trial usually expires.

If it is something for myself and I think it's likely I'll want it I am very inclined to just buy the product or start a subscription, I don't want to be this guy:

https://blog.codinghorror.com/we-dont-use-software-that-cost...

Seen from the other side of the aisle of software development and marketing I see "free" trials as being pretty expensive to offer in terms of management thinking a lot about requirements for them, developments implementing facilities to offer them, as well as taking up headspace of the marketing people as well as keeping sales and support busy talking to customers.