I've had a passion for both the 25 and 6.5 cals for many years. My first 6.5 was a slightly sporterised Mod96 which the Importer here in Australia had shortened the barrel and fore wood on, turned the bolt down and then fitted Lynx steel scope mounts and rings to. It shot like a dream. I hunted with the rifle for several years and it never failed to impress me with it's capabilities.
Actually, the cartridge impressed me so much that I went out and bought a Ljungman AG42B, the semi-auto ex-mil Swede rifle. Fed a diet of the ex-mil ammo (139gn FMJ - which was actually ex-mil target ammo) this rifle really was a piecce of fine machinery. Then I had to sell it, thanks to the EX-wife, but I would have had to pass it in anyway when our laws on semi-auto's went hopping to hell in a handbasket!!!
I now have a 6.5 again, this time a Husqvarna 1942 M38. In great condition with a good bore, it performs better than I can hold at 300Metres. I started feeding it reloads using 140 HP Taipans over Mulwex AR powder but am in the process of changing to 120gn Sierra's instead.
As for the 25 cal, I have always thought the 257Roberts was the ideal all-round general light to medium calibre for Australian game. As such I've got a hankering to add one to the safe one of these days.
So, it was no surprise that I snaffled a 303-25 SMLE barrel for $20 when it came along. The owner had recently converted his No1MkIII 303-25 sporter back to a mil issue 303 for SSAA-CSR comp and no longer wanted the barrel. I had a shot out 303-22 Falcon No1MkIII* which was doing nought, so the switch was made. My 303-25 is rather rough in it's stock work but has nonetheless performed admirably on feral pigs. It will soon have a synthetic stock, scope mounts and a scope, thus becoming my primary hunting outfit for goat, pig & deer.

So, I'd say yes there is a need for both of these as different shooters/hunters have differing ideals on what they want and can handle.