That's a pocket hole jig, and if I was doing pocket holes I would have bought the old K4 with the built in clamp. I suppose the 720 is its replacement. The smaller kit apparently moves about too much.
For dowels I actually use the Wolfcraft Dowelmaster jig, together with a couple of dedicated drill bits that have depth-stop-collars fitted to them at the correct heights. https://www.wolfcraft.com/products/wolfcraft/en/EUR/Products/Attachments-for-Machines/Drill-Guides/Dowelmaster---dowel-gauge-for-wood-joints/p/P_4640
I do use the Kreg shelf pin jig for adjustable shelving, and it consistently gives you perfectly spaced and aligned holes, - make sure you get the European standard 5mm version rather than the imperial sized one the Americans use. You can connect a couple together if you're feeling rich enough to buy several, but I just use one and drill 5 holes at time, then move it.