I must admit, personally I’m not a big fan of 60mm mortars, but it’s not my area of expertise. Most of my light infantry mates think they are great, but my mates with a mech infantry background think they are a bit pointless. Like everything, they have their place but here is an opportunity cost in their use. A 60mm mortar is already in service with SOCOMD and has been trialled by conventional battalions. There is also a project that will introduce a 60mm mortar into the regular battalions. I imagine we will se a 60mm mortar introduced into the light battalions in the next few years.
Having some mortar experience, I agree with this summary. The 60mm is good for providing indirect fire in close country (either urban areas or thick vegetation) and is more difficult to detect considering you can place it behind hills, in gullies or anywhere else provided it has a clear trajectory to fire. Whereas DFSW generally need a clear LOS and are relatively easily identified once they have fired, mortars do not suffer these limitations to the same extent. Their ability to provide top down fires is probably the most useful component - especially if facing dug in infantry where trench systems, sandbags and other fortifications may provide cover horizontally, albeit not vertically.
This being said a 60mm mortar has it's disadvantages. Whilst much easier to carry than an 81mm (which are far less effective when manpacked) the ammunition would still be a limiting factor. If you include rounds for adjustment (which varies, but let's say 5) and then fire for effect (which again varies) then the number of fire missions capable of being conducted when the system is manpacked is severely limited. Additionally the system is far less useful against anything more than infantry or soft skinned targets - noting any effects will be limited to puncturing tyres and penetrating/damaging exterior systems. It would make sense that mech inf may not think it useful when they may have vehicle mounted mortars of a higher calibre (81mm) which provides greater effects, range and capability (noting 81mm can employ airburst, delay and possibly now even precision capabilities). However for light infantry it can be useful, provided any force element is able to carry the necessary amount of ammunition required.
60mm mortar s don't really offer that much of an advantage over 40mm grenades for a grunt IMO.
Its another bit of kit to carry, and although 60mm rounds are small, 40mm rounds are smaller, and allow much easier carry and re sup.
81mm mortars have a range of about 3200m give or take, you have arty support, now "recce" helos, I think there are some good options for 40mm development in our Army.
Milkor MGL - Wikipedia
I believe the use of 40mm grenades in addition to the 60mm mortar would be best practise. Both have their places and are relatively light, making them suitable for light infantry operations. Additionally the advantages/disadvantages of a 60mm mortar (such as flexible location and ammunition quantity) can be offset by the advantages/disadvantages of a 40mm grenade (more ammunition and a need for a clear LOS).
This all being said the 60mm is still overall less capable than heavier systems such as the 84mm, 40mm LWAGL and the HMG. With the move towards mounted operations it would make more sense to adopt vehicle mounted mortars which are more mobile and less exposed to counter battery fire. Vehicle mounted mortars can also carry more ammuntion and can keep up with other mounted units quite effectively. The 84mm, whilst only DFSW, provides a wide range of of heavier capabilities, most significant being it's bunker busting and anti-ARMD roles. The AGL and HMG systems are both effective suppression/support weapons and whilst I'm not truly familiar with DFSW, can provide more sustained fire than any 60mm mortar could.
The 60mm mortar is good for light inf but not mot/mech inf. I can imagine it being highly effective in COIN, peacekeeping or other low-intensity contingencies (where the likely hills, jungles, buildings and other obstacles could benefit from light indirect fire) as well as in higher end urban op, primarily in defence. However it lacks power when facing a peer type opposition or when higher calibre systems can be better utilised.
To my own knowledge the SOTG preferred the 60mm mortar in Afghanistan over the 81mm, probably due to it's light weight.It most likely proved useful in the mountainous terrain and could reliably be carried during arduous stomps from airmobile insertions. The Cove has a good article on the M224 trialled by 3RAR also:
Lightweight Handheld Mortars: A Suitable and Effective Platform to be Organic to Rifle Platoons | The Cove