Why daytime running lights? Well, the more visible you are, the less likely you are to get hit by other vehicles. And that's important.
"...It’s a stance that is backed up by , a company that launched an intelligent daylight back in 2013 and every light since has had a daytime focus. “Daylight visibility has been really important to us right from the start,” the company tells . “When you consider that 80% of cycling accidents happen during the day, attracting attention to other road users as early as possible during these times is really quite crucial. Think about modern cars, they have their lights running almost any time you see them on the road. Why shouldn't it be the same, if not even more important for cyclists?” ... https://road.cc/content/feature/231243-should-cyclists-use-daytime-running-lights-8-best-front-and-rear-daytime
Other vehicles have seen a drop in accidents since the progressive roll out of daytime lights -
"..When it comes to use in vehicles, results vary – some studies show a five to 10 per cent reduction whilst others demonstrate an accident rate drop of 28 per cent. One study carried out by the US National Highway Traffic Safety Administration found at 23 per cent drop in accidents involving motorcycles and cars when day time lights were used..."
And the impact in Denmark -
"A 2012 study carried out in Denmark discovered a 19 per cent drop in accidents when cyclists used permanent running lights."..https://www.cyclingweekly.com/group-tests/daytime-running-lights-373627#U6jFS4E52xOig7aT.99
"Making the use of daytime running lights mandatory for motor vehicles is generally documented to have had a positive impact upon traffic safety. Improving traffic safety for bicyclists is a focal point in the road traffic safety work in Denmark. In 2004 and 2005 a controlled experiment including 3845 cyclists was carried out in Odense, Denmark in order to examine, if permanent running lights mounted to bicycles would improve traffic safety for cyclists. The permanent running lights were mounted to 1845 bicycles and the accident rate was recorded through 12 months for this treatment group and 2000 other bicyclists, the latter serving as a control group without bicycle running lights. The safety effect of the running lights is analysed by comparing incidence rates - number of bicycle accidents recorded per man-month - for the treatment group and the control group. The incidence rate, including all recorded bicycle accidents with personal injury to the participating cyclist, is 19% lower for cyclists with permanent running lights mounted; indicating that the permanent bicycle running light significantly improves traffic safety for cyclists. The study shows that use of permanent bicycle running lights reduces the occurrence of multiparty accidents involving cyclists significantly. In the study the bicycle accidents were recorded trough self-reporting on the Internet. Possible shortcomings and problems related to this accident recording are discussed and analysed."..https://www.ncbi.nlm.nih.gov/pubmed/22884376
So, get some lights on your bike, and use them 24/7 on your ride. Be safe.