My thoughts exactly !!......if you watch the completion shooters insert those long tubed funnels (to insure powder gets to bottom ) then pour a vial and pull tube back out !! Drop 2 pellets and your done !??
Some problems with using pellets in a Gibbs rifle;
1. The substitutes don't ignite easily enough for a Gibbs, or similar LRML rifle. Because of the increased pressure caused by the 90-100 grain charges, combined with the 500+ grain bullets, we have to use platinum lined nipples, with a very small aperture. Otherwise, the backpressure will blow the hammer back to half, or even full #### (imagine all of the hot gas blowing back in your face). Regular nipples burn out quickly. Now, finally, to the point...the small aperture of the nipple, combined with the long flash channel, make it challenging to get reliable ignition, even with black powder. Any departure from proven loading procedures result in lots of misfires, or hang fires. I have not used pellets, but I since they were developed for the inline industry, I assume that ignition was not a big concern in their development. I could be wrong about that...
2. The Gibbs rifle has a chamber at the breech, which is smaller in diameter than the bore. I am unfamiliar with pellets and their dimensions, but it would be a happy coincidence if they actually fit the chamber.
3. You can't fine tune your charge with pellets.
4. Some competitions do not allow substitutes. The US NMLRA, for example, specifically disallows substitute powder. I have no knowledge that the Maple Leaf, or Dominion of Canada organisations do or don't, but I have not seen any mention in their rules posted on line.
I use a long brass funnel, as you mention, and pre-measured charges, and I don't see the problem. Part of what I enjoy about LRML shooting is the attention to detail. It is quite remarkable the difference that small things make, and because we load each shot on the line, we get instant gratification for our efforts, unlike cartridge rifle shooters, who labour away for hours in the dark basement, then go to the range, sometimes waiting hours or days to discover the difference a 5 grain increase in powder charge makes. Understand that the odd things that precision ML shooters do are a product of long experience. Many of the procedures were developed a century and a half ago, and remain in use today, because they work. The Brits, Irish, and Yanks were shooting ML rifles at ranges out to 1200 yards and beyond in the 1850's, and some of us "eccentrics" are still trying today. I totally understand, though, that LRML is not for everyone, but for some, it is an addiction. I know that some of you understand.