I hope this doesn't come across as to bold or arrogant for my first post aside from introducing myself. As always with everything opinions are like fleas and every dog has them

Snipers are an asset that specializes in being covert. A DM in general is more of an overt role especially with the tendency towards presence patrolling. A DM can perform some of the tasks a Sniper fulfills but unless he emerged from the womb ghillied up and leopard crawled past the Doc and out the door he isn't going to have the level of field craft or self discipline required to remain covert for 24-72 hr periods. If he did chances are he has been identified and snapped up by Recon or Snipers already. The other things are a DM does not in general have the training or experience to call in accurate Mort/Arty/CAS and most importantly the ability to understand the higher commanders intent and his role in it. When everything turns pear shaped a DM will revert to his most basic role which is a rifleman with a scoped rifle, a Sniper team is an independent entity commanded by a JNCO which can react to whats going on and has been trained to hopefully be able to deal with drastic situation changes.

Now whether or not you need this covert capability and level of independence in an asset to be deployed depends on what types of operations you are conducting.

Recon detachments are indispensible and I don't say that just because I command one. In general rifle Platoons are noisy messy things that leave a black bin liner worth of rubbish everywhere they travel, rifle sections are not much better. Some Platoons/sections are better than others but none can ever achieve the level of noise and field discipline expected of a Recon det, if they were capable of it they would be in Recon. The discipline required in Recon is the main thing that sets them apart from the rest of the Battalion. Remaining covert for a long period of time in adverse weather conditions or when the pucker factor is high is not easy. A lot of Soldiers can't cut it which is why there are courses to assess possible candidates.

Any rifle section is and should be capable of conducting reconnaissance type tasks but they are not ideal for that role. The size of a section hinders its ability to perform the tasks through the amount of sign it makes and amount of ground it requires when in an LUP. Cutting a section down to a det size to negate this removes a lot of the fire power the commander has until now taken for granted, unless he has spent a lot of time conducting BCDs he is going to be at a disadvantage trying to achieve a clean break. Recon dets don't have this problem they do not have to go out and conduct Sect/Pl IAs and Coy DLOC. All they practice is the different types of BCDs until they become second nature. Due to the size of a det the commander does not have the luxury of sitting back and assessing the situation, he is right there in the fight and has to rely on his teams level of training for the first few bounds until he can get them to grips and start making command decisions.

From my own experience as a commander and DS on patrol procedures courses I would say that 10% of the Soldiers in a Battalion are capable of doing the job well. For most it is the self discipline that lets them down. Enforced discipline can be used but is hard to apply in a close prox OP. Now one could disband the RISTA elms in a Bn and hope that their experience is filtered out to the remainder but that is a pretty long shot. At the end of the day the CO is pushing his Recon assets out to find information about the En and deny the En info on FF assets. If he sends out a C/S that is compromised quickly and does not meet his CIR all that has been achieved is the exposure of his possible intent.