I actually started using Sqlite as my go to SQL db. Logic being, the products I make will never have more than a thousand people that pay me $1/day. For that reason, Sqlite suits me well and will serve my users too reliably.
I'd say it depends more on what you're doing -- if you're not doing a whole lot of writes, you could get really far. See the "websites" section of the sqlite When to Use article: https://www.sqlite.org/whentouse.html
@levelsio website hood maps was able to handle hundred thousands users on sqlite. For stuff you're charging for scale is not issue, as in you won't face that problem.