Putting your coins in a cold storage is good idea. No matter what happens, do not be tempted to sell everything you have if you don't want to live with regrets in the future. You have started a great plan and I hope no matter how the market behaves, even if it move sideways and does take a long time before it recovers, just stick to your goal and continue DCA while opportunities are still knocking on your door. Bitcoin halving and bull run are fast approaching, soon you will come to reap everything what you have been investing.
Not only it can discourage us to sell because it's a bit hassle to transfer our coins or to make a transaction but it can also protect our wallets from malicious threats. I think only those who have tons of Bitcoin on them are doing this. This people have a spare fund outside that they can use on emergency situation so they will never sell their coins easily. For those who aren't like that, they can sell when they badly needed a money as they may lack money outside but they won't also regret it because they use the money on important things.
These people can't do a DCA but they will only buy once there is a money available. It's fine. At least they still try their best, than not investing at all. BTC halving is still far and as of now, there is no signs yet of a bull run. It's not a reason though to not get motivated.
Definitely a smart move, not a lot of people could really understand it completely because they do not understand how it works but if you use stuff like ledger or trezor then you are going to be able to say that you are more secure and that matters. I understand that some people may feel a bit different in that regard and I get that, you do not have to feel the same way and it could reach to a different point, but as long as you could make it work, there is nothing wrong with that at all.
I personally try my best and try to use my ledger as much as I can, it allows me to make sure that I have all my long term holdings in there, I still have some at Binance to trade, but all my long term coins are in my ledger.