Anecdata: Trello and Jira both have free plans that I used that caused me to recommend them for paid usage at multiple companies I’ve worked with. Those free plans resulted in $xx-$xxxx monthly subscriptions. Asana has a paid plan with a 5-user minimum limit. I never bothered to even try it since I wouldn’t have the extended time to play with it. As a result it never even got mentioned to companies I’ve worked with.…
The article specifically mentions free trial periods as being a good idea.
My experience is that I rarely have enough time to determine if I really like the service or if it's still just a shiny new tool to play with. I need more than 14-30 days to actually put in the work to understand a reasonably complex tool (say a CRM system) well enough to make a commercial recommendation.
Obviously this issue doesn't apply to all SaaS companies but it's probably common enough to be worthy of consideration.