Braking with down elevator is simply not a good way to do it. I have done it back in the day when I had little radios and ran out of channels. I would never do it now with the technology we have now.

cons
1.makes the ass end of the plane lighter that reduces the effectiveness of the brakes.
2. puts lots of pressure on the little nose gear. This makes steering suck and can lead to snapping it if you have a side load and hit a crack.
3. If landing hit the last thing you want is down elevator. This will cause it to bounce causing more damage.
4. it’s a bad habit to cram down elevator when just touching down. Say a gust brings the plane back up while you are moving the stick. All bad.

pros....
1.well it saves a channel.
2. guess it can be easier for some.