The other day I was having a hit with a colleague who was at a substantially lower level than me. In order to keep the rallies going, I slowed down my swing through the ball a lot so that I could take the pace of the ball. I found myself hitting really clean forehands and getting into a really good rhythm. I have tried using this method of slowing down rallies against my regular training partners and find that it really helps me get into a good rhythm . Is this a good way to warm up/ continue hitting or does it make you get used to hitting at a lower pace?, i.e. although it temporarily helps in getting into a good rhythm, does it actually make you worse at reacting to balls that are hit at a normal pace.
100% it's a great way to warm up and keep it going. In rallies it's actually a great weapon to have the ability to slow down the ball and catch your opponent off guard, but depending on the level of player you're up against they may be able to spot the slower shot and counter it and hit a winner against you.
I recommend having versatility in your game, but keep hitting at a higher level where possible. I always do this when warming up, just as you mentioned it helps with rhythm and gives you great confidence.