Hmm, that sounds like time travelling
But as already mentioned: your journey doesn't become any faster.
I just looked into some journeys from the UK to Malmö as an example. Leaving on the evening of day 1 in Southeast England obviously means taking for example the last Amsterdam-bound Eurostar of the day at 17.19 from St Pancras, which arrives on Brussels at 20.12. At that late time of day your options to get to Sweden are limited and hardly any of them is really comfortable: one option is to stay on Eurostar till Amsterdam and continue after a short night (departure at 5 in the morning), the alternative from Brussels involves multiple changes in the late evening and even waiting 2 hours in Duisburg in the middle of the night.
A journey via the ferry allows leaving even 20 minutes later from London, and after a full night sleep one can travel significantly more comfortable (more international ICs instead of stoppers) towards Sweden. And that's even with a not very optimistic travel advice, as it is planning with a 2 hour transfer from Hoek van Holland to Rotterdam. However journey times with Metro B from Hoek van Holland to Rotterdam are significantly shorter than 2 hours, which results in a more robust change in Amersfoort than indicated by the journey planner. (For some reasons it gives me the domestic 5 minute change instead of the advised 35 minute, or 20, minute change for international journeys).