Many people can't afford to take the day off for voting. And even mail ballots are allowed, making the process easier would encourage more participation. Is this not a problem worth solving?
Sure, but can't that be solved for most people by holding elections on a Sunday and keeping the polls open from 08:00 to 20:00? That way it is only a small percentage who are unable to vote.
Sweden has this plus early voting and we have between 85% and 90% participation in our elections. The early voting of course make it easier to manipulate votes.
That's not actually possible in the sense that declaring a day a holiday doesn't actually prevent employers from giving people shifts. If anything, restaurants and stores actually retain more staff during holidays. The only people a holiday would affect would be people working high end jobs that probably wouldn't have issues voting anyways.
Vote by mail and extended voting hours are much more effective solutions for people who otherwise couldn't find the time to vote.
Fine, bring out the heavy law-making artillery then. Make it mandatory to give staff time off to go voting with heavy penalties for non-compliance and some kind of nice carrot for compliance.