Hi Evepym -
<<"We will be arriving Lucern on 23rd Dec at 3pm as mentioned above for preparing Christmas countdown day. Meaning that 23rd & 24th are staying in Lucern">>
From the perspective of the festivities and surroundings, it will be a lot more convenient to stay in Luzern itself. Possibly, you could leave some of your luggage at Luzern Main Station, so that you would not have to take it to the hotel and back.
And,you might take only light luggage to the Jungfrau region, if you choose to ship some to the airport rail station, or to Zürich main station. Most likely to be shipped on the 24thfor pick up the 2nd day after you ship.
For lockers at Luzern and the other main stations:
For various luggage transport services:
And, if you search under Stations and services for an individual station name, the SBB website lists what ever storage faclities exist at that station.
From the standpoint of much lower cost and also quicker transportation to Interlaken, but not in the midst of the festivities in the city, I'd consider a station along the line from Luzern to Interlaken. I have recently used an inn in Sachseln which is of good quality, has reasonable prices....much cheaper than Luzern..... and 3 trains to/from Luzern every hour. The high costs of staying in Luzern are an issue for some people. The trains take either 26 or 34 minutes to make the journey.It is a bit over 200 meters from the station, which might be an issue if your luggage is considered. It is the Gasthaus Engel on the Brünigstrasse in this map.
You will also note the bus stop for the bus that goes top the station, if you need it. Mouse over the icons for information
So, as you can see, if "better" means "cheaper" staying outside the city is "better." If it means being in the midst of the festivities, it means that staying in the city is "better." And, the SBB offers some luggage services that might help make your trip easier. Note that there are no luggage services at Sachseln station.