Copenhagen has a lot more to offer for visitors than Malmo, so I assume that you will be travelling to Copenhagen on most if not all days.
But as you will be close to the station then this is not difficult with the train, which does not take too long, about 40 mins to Copenhagen-H from Malmo-C. Of course, you then need to get to/from your hotel and destination on each side. There are about 3 trains per hour.

So as long as you have plenty of time and are prepared to factor this in, then it can save you money on your hotel. But, with the fare costing about 111 Kr each way per person then this will soon add up! So you need to calculate what will be cheaper and easier for you after you have factored this into the cost. Oh, and there is no discount for seniors!
You might be able to get it cheaper if you look for a multi day ticket, but you need to ask at the ticket office as there is no information about this online.


Also be aware that there are still border controls when travelling from Denmark into Sweden, so make sure that you always have your passports with you.