I see little point in going abroad. I can't see how training and playing under baking heat is good preparation for coming back here where (last couple of weeks aside) the weather is totally different. Ok, so maybe it allows a bit of "bonding", but we never seem to have had any trouble in that regard. I think it's probably become more of a kudos type deal...and a means to getting clubs to pay for players summer holidays!
Our pre-season so far has seen the team pitted against increasingly physical opposition, but that's probably as much to do with luck of the draw and who was available when as it is anything else. It's all about getting the players game time to blow out any cobwebs from the summer; getting a look at new players in a competitive match setup and experimenting with positioning and maybe a few things from the training ground.
Whilst "glamour" ties are great for the fans and maybe even a chance to make a few quid from pre-season, they're not going to achieve much else.
The Charlton game is, I imagine, a chance to piece all the bits together and get a look at what you might think would be the starting squad for the league against an opponent which is more on a par with that level of competition.